Easiest way to do that is to ask one of your friends you know is computer savvy.
Either that or research the problem online for solutions.
The only way you're going to get rid of the viruses is to get an Anti-Virus suite on your computer, I recommend AVG. AVG Free Advisor - Free antivirus and anti-spyware downloads
And if you can't get the computer fixed, back up what you can, and wipe and re-install the OS.
The best way to keep your computer clean is prevention. Use Any other browser other then Internet Explorer. Virus scan anything you download. Only download from sources you can trust (Like Bittorrent or sites like Filefront), and do routine scans for spyware and viruses.