It is odd that only some web pages are working. Are you sure you are not just seeing cached versions? If you hit the refresh button, do they refresh properly? If they do not you can access no web pages, which might indicate that you are being redirected to a proxy server by malware. If you can get to pages by entering their IP address but not their URL, you might be being redirected to a DNS server by malware.
Run Hijack This to detect and (with luck) remove malware. You can get it from http://216.180.233.162/~merijn/index.html.
Failing that, then a rebuild of your PC might resolve the issue but that is of course a drastic step.
Edit:
If you do run Hijack This, be aware that it lists everything that might be malware, including a lot of stuff that is necessary. So don't ask it to "fix" anything unless you're sure it is unwanted.
Another possibility is that your PC is running something like Cybersitter configured to bar access to game-related web pages, but since you say you're working I assume that's unlikely:)
Run Hijack This to detect and (with luck) remove malware. You can get it from http://216.180.233.162/~merijn/index.html.
Failing that, then a rebuild of your PC might resolve the issue but that is of course a drastic step.
Edit:
If you do run Hijack This, be aware that it lists everything that might be malware, including a lot of stuff that is necessary. So don't ask it to "fix" anything unless you're sure it is unwanted.
Another possibility is that your PC is running something like Cybersitter configured to bar access to game-related web pages, but since you say you're working I assume that's unlikely:)