I am running windows xp in a University Local Area Network.For a few monthsI have been loosing my internet and my ability to play LAN games but I am able to access my network with ease.I got back my previous settings by restoring my PC to an earlier date.
A few days later my system restore failed.This process has repeated twice giving me no other choice but to reinstall my XP.Now that i have reinstalled my OS twice,I want to make sure this does not happen again.
So if somebody could make out what could be the cause,please help me.I do not want to reinstall my OS again.

Are you up to date with your antivirus software?
Have you got adaware and spybot?
Are you running a firewall?