My PC has a worm!

reformat, always a good move

Imo best thing to do would be to download and burn (on another pc) a bootable Anti-Virus disc (Kaspersky, ESET and others have such options). Than boot your pc from that disc (it's normally got Linux inside) scan and kill the virus. If by chance the exact anti-virus brand would not be able to deal with your virus, try another one. Oh and all those disc images are available at the web-sites of the appropriate anti-virus producers for free. :) Also, if you're on a laptop with no disc-drive than you can create and use a bootable flash-drive for the same purpose.

My pc has worms world party, and you don't hear me complain.

Breed some chickens. Chickens love them some worms.

Microsoft's AV is a piece of poop. Get a real AV next time and don't watch that much porn...

Like others said, do a scan in safe mode. One of the biggest pains in the butt about worms is that as you scan, it's going to multiply numerous times and be all over the place and its very likely at least one part of it is hiding somewhere that a scan can't take out unless you are in safe mode.

Also keep in mind that for many viruses, the amount of time you will spend cleaning them up is going to be more time than you'd spend backing up and doing a format. If you go this route, make sure any files you back up are clean and move them off the affected drive (though some worms will affect all storage, and some will stick only to your c drive). Emailing stuff to yourself actually can work rather well for backup when you have a virus since most email programs check for viruses before sending and downloading an attachment.