Does it go fast normally? I just moved to an apartment that has waaay slower internet, and, me being the internet fiend I am, I go too fast for it, and it doesnt load some pages until i refresh them like 6 times. And obviously loading videos is slow as hell too.
Is the internet connection shared? that can cause a lot of problems
if you are on wireless, maybe someone is using it without permission
No matter what the problem, the first thing I would do is unplug the power cord to your modem for 30 seconds and then plug it back in. If that doesn't work, you can unplug the power cord to your router for 30 seconds and try again.
I've had that happen before...I could go to google, this site, and like newegg...but every other site, even big ones like yahoo and msn would get network connection errors. It'll fix itself after it marinates.