I trued sharing my internet connection with other computers with my default connection on the properties advanced tab which says allow other computers to connect through this network but after some minutes i discover that it just stops working.Any help will be appreciated

The reason for this problem can be determined by answering these two questions
1. What type of modem do you use?
2. How many systems use the internet sharing?
Your reply determines my answer

I use starcomms Izap with 5 Computers.

sharing the internet connection on windows is simple and just clicks away. I use a software to that, the software is ---click here to read more---

Actually systems , 5 systems isn't too much.  But since you modem is starcom izap try the following.
-Set up your network
-Connect the modem to the internet on the system acting as your server
-After the connection has being established share the modem as normal from the Network connections window  while the modem is connected.
-This will cause a pop up window to display that settings will not take effect until you reconnect click yes.
-Then try to connect from your clients
-This should work
If it doesn't, then reach me on 07062578879 for live help.