computer virus

A few minutes ago my son was playing games on the computer and, he asked me if he can download more games in it. I said no. He likes to download anything on our computer and I get mad because it gets slower and slower. My husband said that our computer has virus in it and it needs to be check. I know he is right, I might check the www.iolo.com for their service and tune-up for my computer. I think they can do the job. Sometimes I do not like if my son use the computer, but he likes playing games.