Stay ahead of the curve; download Windows 7 and hope nobody has written a virus for it yet.

What about an OS OS... e.g. ubuntu

Could it be problems with port forwarding? IM ports may be open whilst others are blocked?

Have you got some rogue proxy settings buried somewhere? Try telnetting to some website's port 80.

I can only send my sympathies. Get a professional in to fix it and write the cost off under the heading "Education".

Download Malwarebytes' Anti-Malware. I shit you not, its what all the antivirus forums will advise you to use.

http://malwarebytes.org/

This kind of blocking can be caused by a software firewall.

I would re-install any antivirus/firewall software you have.

I take it System restore isn't helping because it often solves these types of issues.

Have you tried using different DNS servers? I use www.OpenDNS.com and it works fine. This could be a DNS failure at your ISP.

Failing that, something is blocking port 80, as mentioned above a rouge setting in your firewall or router.

I also get a similar effect if I have booted my PC into windows (not something I do very often) the network card gets stuffed and requires a shutdown and power cable out to reset it.

So it's also possibly a network card failure.

have you tried remoing your router from the equation? could be a fault on the router? not likely if other PC's still work through that router though.

I've had similar in the past (and got Jennie's PC infected with one once as well, still not completely shifted it).

But if you can't get to any websites, then it's either ports as above, firewall as above, DNS server or the HOSTS file—a lot of malware does dodgy stuff to your DNS records and HOSTS file these days, makes it tricky to shift stuff again afterwards.

If you don't know where your hosts file is, look in c:\windows\system32\drivers\etc

You can actually just delete it. The advice for using MalwareBytes is also a very good one. I also suggest getting and running CCleaner to clear out your temp files, do that before running MalwareBytes since it'll reduce the scan time.

Also, no, really, sit back and ponder why exactly you're using Windows. Maybe you have a good reason, but also you might just be doing it out of inertia. Personally I dual boot Vista and Ubuntu. Working primarily in Ubuntu, and switching to Windows when I want to play a Windows only game or use some software that won't cooperate with wine.

Best of luck!

Cheers for the advice people!

MalwareBytes is an absolutely brilliant program, I highly recommend it. It cleared all of the last vestiges of the virus from both systems, in combination with a dedicating win32/virut-removal tool. I managed to fix the browser issue by calling a little utility that resets the TCP/IP stack.

Everything works again now, with the exception of a few programs that need reinstalling. No major lasting damage though... phew.

And you call yourself a scientist ?! That suggestion about Ubuntu is right, get a Linux distribution or OpenSolaris. Not only will those virii be gone but you'll be able to do all your work on LaTeX and use EMACS for everything like geeky scientists do. Not to mention those ASCII games.

I already do all my work in LaTeX - in Windows :)

To be fair, this is the first big virus incident I've had for ten years, and it only happened because of my own immense stupidity... Windows is pretty secure if you use it right.

My daughter's laptop got one like that, after she had turned off all updating so that both XP and Norton AV were running on 2005 packs / profiles. I think probably they slowed up her internet connection and/or prevented her from dowloading mp3's.

A very kind geek at the office swapped out the HD and recovered her data.

Sigh.