Do you know how to get rid of this?

Asked by kayyyyleigh (404) October 29th, 2009 from iPhone

my computer has had a virus for a while. well two, that I know of. one is called Security Tool and the other one is called Skynet. I’ve tried many antivirus programs and security things but nothing gets rid of them. and I need my computer desperatly for school. can anyone help me:/? thankk youu.