Has your Android suddenly gotten stuck on its startup screen and wont load past its logo? Does your phone restart over and over again and simply refuses to power on correctly? Here are some possible reasons why this may be happening as well as some suggestions on how you might be able to fix it.
Disclaimer

I try to avoid giving advice about software manipulation and or customization but I get asked for help regarding this type of issue a lot. Since there is very little documentation online about how to try and troubleshoot or resolve these types of problems once they have occurred (whatever the cause may be), I decided to write up this guide to be used as a reference on how to try to combat this annoying issue.

Have no illusions though, as you probably already know, this issue can be extremely annoying and stubborn and can be one of the more difficult issues to try and resolve on an Android smartphone. If you find the information in this guide informative or helpful then PLEASE let me know by leaving a friendly remark in the comment section below this article and by sharing it through Google +, Facebook, Twitter or by linking back to this page from somewhere else on the net. It helps others to find this guide and with any luck gives them a chance at fixing these types of issues as well.

That being said let’s roll up our sleeves and see if we can get your cell phone to turn on and work properly again.
Possible causes as to why your Android won’t turn on properly

There are a few reasons as to why this issue might creep up on an Android smartphone so let’s start with some of the common reasons and go from there…
Software customization or manipulation

One of the many things that make Android so great is that the operating system and software on Android devices (especially smartphones) is very customizable. Android phones can be unlocked, rooted, flashed and tinkered with and are one of the most flexible operating systems available for smartphones to date.

If you have taken it upon yourself to tinker or change the software on your Android smartphone then you have taken the risk of running into annoying software problems such as this. Luckily Android smartphones are very resilient devices and it is difficult to “brick” an Android to the point of it being completely inoperable.

If your cell phone is stuck in this boot loop or refuses to power on properly after you have attempted to edit or change its original stock operating system or software then it’s likely that something did not go right during the procedure and standard troubleshooting including a factory data reset is not going to help solve this particular problem as the issue lies with the software itself.

If you are following directions online regarding this customization process and these instructions are from a trusted source or at least seem legitimate then you might want to try doing whatever it is you did again starting from the beginning.

There might have been an error or glitch in the process, sometimes completely outside of your control, and starting over from scratch might just be the answer that your phone needs to correct the problem. If you cannot get the customization to go through properly then you might want to consider reverting back to the original software that was intended for your phone.

Just make sure to review the entire troubleshooting portion of this guide first as there are a few things that you might want to consider trying before starting over again.
Android stuck after software updates

This is one of the more common causes that can trigger this issue to happen on an Android especially if the update did not get to finish properly.

There are many things that can happen which can cause a software upgrade or update not to finish correctly including:

The computer being used to apply updates froze or powered off during the procedure.
The phone was unplugged from the computer before the update was finished.
The phone froze during the update and didn’t get to finish properly.
The phones battery ran out before the phone was finished with the installation.
The update was interrupted for whatever other reason(s) causing the installation to fail.

Many Android smartphones have some type of warning message emphasizing that updates can take time to complete and should not be interrupted. Many Androids will not even allow an update to take place unless the battery is charged to a certain percentage just to avoid any complications during the installation.

To avoid issues with updates in the future feel free to review how to avoid complications when updating the software on an Android smartphone for more information.

In any case if your phone was interrupted during an update or if for some reason it didn’t get to finish properly and/or no longer works properly then the software that your phone uses to function may have become corrupt. If this or a similar situation has happened to your smartphone then you are in the right place and should proceed to the troubleshooting section below.
Bad or Troublesome Applications

Do you remember recently installing or updating an application before this issue started?

An application that’s installed on your cell phone might not be getting along with a new update, it might be conflicting with other apps, it might be malfunctioning or outdated itself, if downloaded from somewhere outside of the Google Play Store it might even contain malicious code such as a virus.

In any case, locating and if necessary removing troublesome applications is going to be one of the first things to do when troubleshooting software related issues on and Android including this particular issue.
Software Bug, Glitch, or Virus

If your phone just suddenly powered off for no apparent reason and then wouldn’t turn on again then it might simply be the result of a software bug or glitch which was completely outside of your control.

If however something has found its way onto your phone and is causing problems then that something may be the cause as well.

These types of things can be difficult to notice much less locate and eliminate but don’t fret the troubleshooting steps listed below can help with these types of problems as well.
Defective or Malfunctioning Memory Card

A very uncommon but easily overlooked cause could be a defective or malfunctioning memory card. If your phone is currently utilizing a memory card (like a MicroSD Card) then try to power off your phone and then remove that SD card. If your phone is being stubborn and wont power off then try removing the battery, if your phone allows you to do so.

After the memory card has been removed try to turn the phone on and see if it will boot up properly. If it does then you have narrowed it down to an issue with the memory card (or memory card port on your cell phone) and I suggest that you back up the important information stored on your phone to a computer (just in case) and then you can start to try and troubleshoot that memory card.

You can check and see if reinserting the card leads to the same problem, if another memory card will work properly in your cell phone, if a PC will read the card properly, or if reformatting the card seems to help etc. If you narrow it down to a malfunctioning or defective memory card then you might need to look into buying a replacement SD card.
Trying to fix the dreaded Android boot loop
Soft Reset

Start with a soft reset. A soft reset can sometimes resolve minor software issues and should be the first step to take when troubleshooting an Android smartphone.
Power Cycle

Chances are you have already performed a soft reset by attempting to power your phone off and on or by merely restarting your cell phone. If you have not already tried this then go ahead and do so. The solution might be as simple as rebooting your smartphone.
Battery Pull

If possible try removing the battery from your cell phone for 10-15 seconds then reinsert the battery put your phone back together and then see if it will power on properly. If the phone powers on correctly then enjoy your working smartphone.

If your cell phone has a non-removable battery (not all Android cell phones are designed to have a removable battery these days) then you may have to do some research to see if your smartphone will allow you to perform a instead. If this option is not available then you can skip this step in troubleshooting.
Safe Mode

Safe Mode is a feature on most Android devices that allows the phone to boot up without any third party apps or programs and on its original default settings. This is a powerful tool when troubleshooting an Android device as it helps disable and rule out problematic applications.

If you have an application on your smartphone that’s causing problems and not allowing the phone boot up properly then Safe Mode will disable that app on the startup and allow you to access the phone, remove or uninstall that application, reboot and be good to go. Best of all there is no unnecessary loss of data.

You can read more about this feature at How to use Safe Mode on an Android Smartphone but to enter Safe Mode on an Android cell phone you’ll basically need to power the phone off and then hold down a certain set of keys (such as the volume or power keys) which will instruct the phone to boot into Safe Mode. The key combination that you will need to use will depend on which cell phone you are using and may differ depending on what version of Android the phone is running on.

It would be very difficult for me to list all of the methods commonly used for activating Safe Mode on an Android smartphone so if you are unsure what method to use for your specific phone then a simple search online would be your best bet at finding the proper technique for your particular smartphone.

Note: I humbly request that you please do not ask me how to activate Safe Mode on your specific smartphone, it’s very difficult to keep up with those kind of requests and I plan on writing an article listing the most common methods for this topic but until then Google’s Search Engine will be your best friend in accomplishing this task.

Once you have located the proper method to use in order to boot your phone into Safe Mode, you should attempt to do so.

If it works and your phone turns on completely then you should locate the latest piece of software, the latest app downloaded or updated, any new themes, etc that have been added to your cell phone and uninstall or remove them from your device. Then restart the phone and see if it will boot up properly. If it does then you have located the cause and you can enjoy your working smartphone. If it doesn’t work then you might have to enter Safe Mode again and do some more searching in order to find and remove the culprit.

If you cannot access Safe Mode on your particular Android for whatever reason then continue with the suggestions below.
Wipe the cache

Try to wipe the cache partition of your phone using the Android System Recovery tool. Accessing the system recovery tool is going to vary from device to device so if you are not sure how to access this tool on your specific smartphone then much like accessing Safe Mode a quick Google search may be required. Again, I humbly request that you please do not ask me how to activate the Android System Recovery tool on your specific smartphone. For a list of common methods you can refer HERE or read more about what the Android System Recovery tool is and how to use it by clicking HERE.
Wipe the Dalvik cache

If you have recently tried to flash a new ROM to your phone and have CWM (ClockworkMod Recovery) installed then don’t forget to access the Advanced menu options under this tool and select the wipe dalvik cache option and then confirming the wipe if necessary. Your Android might be attempting to use the older Dalvik-cache which could be the very reason why your phone is getting stuck in this bootloop.

If you have never installed CWM on your phone, have never tried to flash a different ROM to your phone or simply have no idea what I am referring to then you can skip this specific section of troubleshooting.
Manufacturer specific PC Suite

While not every cell phone manufacturer offers PC software for their phones many manufacturers offer this service to their customers.

Samsung offers Samsung Kies for its smartphones, Sony Xperia smartphones can use Sony’s PC Companion, LG phones can utilize the LG PC Suite, and so on and so on.

These programs allow you to sync your phone to a PC to accomplish many different tasks including software updates, transferring media files like pictures and videos from the phone to the PC, or manage the phones music library, create backups for the device and in this case the program can be used to troubleshoot the phone when problems like this happen.

If you are unsure if your smartphone can use one of these programs then one of the best ways to check is to do a search online for “Manufacturer PC Suite” where the “Manufacturer” is the manufacturer of your particular cell phone.

If your cell phones manufacturer doesn’t offer such a program or the program that they offer doesn’t help fix your phone and your smartphone still refuses to boot up properly then you should consider performing a hard reset.
Hard reset

A hard reset is designed to remove all the user data from an Android smartphone and return that phones settings back to their original factory defaults.

A hard reset is often part of standard troubleshooting as it can help to solve most software related issues that can occur on an Android smartphone. Since this particular issue is almost always a software related problem a hard reset can sometimes solve this problem depending on what is causing it to happen.

You can find a list of hard reset commands or hard reset methods that are commonly used to hard reset Android cell phones which the settings cannot be accessed at.
What a hard reset CAN fix

If your phone not powering on properly is the result of something being added to the phone which is causing trouble then a hard reset should resolve the issue as it will remove whatever is causing the problem from the phone. This is a great solution for eliminating viruses, bad or outdated applications etc. unfortunately a hard reset does not discriminate between what information it should remove and what it shouldn’t.

You can read more about the effects and the results of a hard reset HERE but in essence a hard reset is going to remove all the user data from the phone, including pictures, videos, music, contacts etc. and returns the phone to the state it was in when it was brand new right out of the box.

So whenever possible you should try to use Safe Mode to eliminate and resolve these types of problems as Safe Mode is supposed to disable third party programs (that didn’t come with the phone originally) and prevent them from running allowing you to troubleshoot. If you are able to use Safe Mode to get into your phone then you might want to take some more time to try and locate the problem and resolve it this way.

If Safe Mode is not an option or is ineffective then sometimes performing a hard reset is unavoidable.
What a hard reset CAN’T fix

A hard reset is usually a last resort and like I mentioned earlier it can be a powerful tool in troubleshooting as it can help solve many different type of software related problems. There are some things that a hard reset will not and cannot fix however, including any software problems that are the result of the phones operating system including its firmware, bootloader, ROM, version of Android, etc.

So a hard reset will not help resolve any problems that were the result of software customization or manipulation (as mentioned earlier). If you tried to install a custom ROM, unlock, flash, or customize your phones software and it then started to have issues turning on properly then a hard reset is not likely going to solve this problem.

A hard reset will not help remove software updates or upgrades. So for example if you upgraded your smartphone from Android 4.4 KitKat to Android 5.0 Lollipop a Hard Reset will not reset the phones version of Android back to KitKat. The phone will remain on the latest version of Android.

If a software update or upgrade was interrupted during its installation then it could have resulted in corrupted software and more advanced troubleshooting may be required in order to fix it.
More advanced troubleshooting

After attempting all of the suggestions listed above (including or excluding a hard reset) this advanced troubleshooting section should help to get your cell phone to power on properly once again and get your cell phone out of the dreaded bootloop.
source: http://bitprimesolution.com/how-to-fix-an-android-thats-stuck-and-wont-boot-past-its-logo/

What nonsense

You this OP, are you just getting used to the internet? Why all this epistle on a simple and forward procedure? You did the same thing in that you silly SD Card thread!

Mr copy and paste, I doubt if you read all that before even highlighting them.

*smh* Everyone wants to have a thread on NL.