Browsers not working

Hello,

I bought this computer about coming on two years ago, Up until about April my internet connection was fine. To at which point I had little to no ability to browse on any browser, Although other computers on my network could connect just fine. I could ping just fine, Firewall was off, had no other problems. Couldn't figure it out so I went with a reinstallation, after reinstalling the problem still persisted. I'm running windows xp sp2 and have McAFee security center wich I just uninstalled which did no good. I tired winsock to no avail. I've tired searching around, but the only people with the same problem as I seem to be running zonealram and reconfiguring settings for that fix it for them, but I do not have zonealram so that doesn't work for me.

Any help would be much appreciated.
Configuration: Windows vista hpme premium
Firefox 3.0.1
IE7