You can use a free anti-virus, but I haven't used them before so I don't know how they work...OR, you could try a free 30 day trial with either Norton Internet Security 2011, Norton Antivirus 2011 or Norton 360. I've been using Norton for about 3 years now and it's cleaned up my PC (I had one trojan horse) and has kept me protected since then.
You may not be looking for something that'll just last 30 days, but hey it should get rid of your virus(es), and while you're protected just look for a good, free anti-virus if you don't want to spend money paying for a year of Norton after the trial ends.
Here's the
link