Web pages load blank

Not sure if this is the right forum, so please move this topic if it's not.

My problem is that I'll turn the computer on, and be able to surf the web for a little bit, but then every page I go to just loads blank. Completely white, the page title doesn't come up on the tab (using firefox) just the complete page address. Everything else using the connection works fine. (AIM, online Games) it's just web pages that don't show up. Once this happens it doesn't matter what browser I use, they all load blank white pages. The problem fixes if I restart the computer, but after a few minutes of surfing, will start happening again.

Anyone have any ideas on why this is happening? Just to note, I am using a router, but the other computer on the same router doesn't have this problem. Both are running XP Pro.