There is a virus going about. It's the Conficker virus. Top be honest, your chances of being effected are about nil. The concern about this one is that it's not been entirely possible to stop it. It can be detected and removed by every major anti-virus software, but if it isn't removed, it calls home for instructions. Normally it's quite trivial to block all the places it calls, but this time, there's so many (50,000 or so) that it's been hard to pin them all down.
And that's the basis of the concern about this one. It's thought that it may activate on 1st April and so some bright spark has come up with the idea that if your computer's not on, then it's not at risk. But that's just nonsense. Sure your computer can't do anything if it's off, but you're going to switch it back on again sometime.
Whenever you see a computer story in the news, you can bet that it's nonsense. Journalists aren't experts in any subject, let alone computers. They're just reporting what they've been told and trying to phrase it in language that actually understand, so quite a few details get missed.
Anyway, the short version of this is that you're not at risk. Run a virus scan if you want to feel more secure, but otherwise there's nothing to worry about. If the threat was going to be large, we'd all have heard about it from a more reputable source than Fox News.
If you like, you can read more information here (also links to free tools to remove it):
http://en.wikipedia.org/wiki/Conficker
There is nothing whatsoever to worry about. If your computer has been updated since October 2008, then you're fine. Watch and see all the computer experts on here run about copying and pasting the same answer to every virus question in the hope of bumping up their score without having to do any work.