TCP Error making computer unusable

[BusterStacks]

Alright gentlemen, this is a problem I have no idea how to fix. Every once in a while, usually while I'm asleep, my computer will randomly stop getting internet access. I have to restart before I can use it again. When I click on a web page in firefox after my connection goes down, it doesn't even attempt to connect, it just does nothing. However, things like AIM will sometimes remain connected. [img]/images/graemlins/confused.gif[/img]