Wireless connected but can't use MSN/Firefox

Hello,

Tonight I was checking the usual stuff: hotmail, facebook etc, no problem. I then listened to music while studying for about an hour, and when I went to check the score of a hockey game online I couldn't access it. Firefox said something like could not find the file job:user///C:/ etc etc. So I tried to get onto IE and it wouldn't work, and my MSN was also down. Wierd. So I searched it up and I found that it was the ask toolbar or something like that and I uninstalled it and deleted the file from my computer and that fixed that problem. The thing is, Firefox and IE STILL refuse to connect to the internet. I've searched and done EVERY suggestion. I deleted vuze from my computer, I uninstalled AVG, I uninstalled winamp, I installed and ran Malwarebytes, I installed and ran Winsock repair, I have gone into run > cmd and reset the reset log and internet proxys. I ran AVG three times before I uninstalled it: nothing. I ran Malwarebytes: nothing. I heard there was a problem with Norton but this computer has never had Norton. I've tried changing my DNS setting to a fixed setting: nothing. My network connection is "excellent" and I'm using a laptop right now beside my computer so the internet is working. When I troubleshoot with MSN messenger it says that my "default gateway appears to be offline" but I don't see how it could be fine one second and messed the next... SOMEONE HELP ME PLEASE!!!!