I'm going to leave the forums up and just focus on the site for the moment, and if that doesn't work I'll reinstall the forums as well. And yes, I can leave a 'sorry we're not available' message.
EDIT: In light of a message I received, it's struck the forums as well, so I'm going to take everything off the server, and reinstall bit by bit. Sorry for this guys, but It's the only way I can be sure of removing it. Don't worry about posts and data, they're stored on SQL databases which I don't think the virus has got to.
I will try to get the site, starting with the forums, back up tonight, but I can't make any guarantees. The forums at least will be up by tomorrow though. Thank you.