even if you have an anti-virus it's not going to help you can't remove a virus when it's running, safe mode doesn't work with all anti-viruses, i suggest you have an alternate operating system even if it is just a live disk then use any av that floats your boat get a decent anti-virus with some 1/2 decent on access protection and you won't get viruses in the first place
i use avast with it's awesome unstoppable bootscanner and i've never had a problem exept it picks up all my mail-bomb tools and stuff