Internet running REALLY slow

Hey, everybody, yesterday I noticed a significant decrease in the speed and stability of my broadband connection. Now, there a few possibilities that lead to this problem, but I'm not sure where to start.

But first, I'll start with the problem: My broadband connection is going REALLY slow, I get a lot of ping timeouts now (for example loading two windows of the tomshardware page will lead to a crash) and I can't visit some sites anymore (cannot find server message). But what really makes me confused is that I can still play games online, just like I did before this glut (eg ping of 60 before and after).
I'm really frustrated at the fact that I can't visit some websites that I could do before hand (eg some forums and anandtech.com)!

Now, I'm running two computers off the same LAN switch/wired router, and these problems affect both computers! On top of that, both computers have AVG AV as their only AV, and nothing was changed that could cause this.

Now, I've got a few ideas that might have caused this problem, so give me a yell if I'm right:
a) Yesterday the router's cables were pulled out before shutting of the power, which may have caused settings to be lost?
b) My ISP are having problems with their servers?
c) It's a virus?

Please help, these issues are driving me nuts!

Thanks in advance!