Cannot open Microsoft Sites?

Currently I’m having problems opening any Microsoft-related sites on my computer. These include Hotmail, Google, Facebook, etc.

I downloaded IE7 yesterday so I thought this could be the problem, but I can’t open these sites on Firefox either.

Oh yes, and Windows Live Messenger won’t work either! (when I check troubleshooting, it says there’s an error with my Keyports)

Any suggestions of what I can do to solve this problem?