Internet Connection Problems!?!?!?

Okay so a couple days ago i reinstalled a fresh copy of windows 7 into my laptop and it was working fine with all the programs that i had. Then all of the sudden one day mozilla wouldn't work and then i started to realize it wasn't just mozilla it was aim, ares, and every other program in my computer the only program that works with internet is Internet Explorer which in my opinion isn't too great. my cousin and brother can use the programs on there computer with no problems at all, so i know its my computer. This is the 3rd question i've posted about this problem and no one has had a way to fix it. Any Help Would Be Greatly Appreciated .