1. Click on Start in the bottom left hand corner of screen
2. Click on Run
3. Type in command and hit ok

You should now be at an MSDOS prompt screen.

4. Type ipconfig /release just like that, and hit enter
5. Type exit and leave the prompt
6. Right-click on Network Places or My Network Places on your desktop.
7. Click on “properties”

You should now be on a screen with something titled Local Area Connection, or something close to that, and, if you have a network hooked up, all of your other networks.

8. Right click on Local Area Connection and click properties
9. Double-click on the Internet Protocol (TCP/IP) from the list under the General tab
10. Click on Use the following IP address under the General tab
11. Create an IP address (It doesn’t matter what it is. I just type 1 and 2 until i fill the area up).
12. Press Tab and it should automatically fill in the Subnet Mask section with default numbers.
13. Hit the Ok button here
14. Hit the Ok button again

You should now be back to the Local Area Connection screen.

15. Right-click back on Local Area Connection and go to properties again.
16. Go back to the TCP/IP settings
17. This time, select Obtain an IP address automatically
18. Hit Ok
19. Hit Ok again
20. You now have a new IP address

With a little practice, you can easily get this process down to 15 seconds.

P.S:
This only changes your dynamic IP address, not your ISP/IP address. If you plan on hacking a website with this trick be extremely careful, because if they try a little, they can trace it back.

You can use this trick if you're downloading some resources and you see the message of daily limit reached for IP

good info