My computer won't let me install any of my Sims 2 games... Why?

I'm 14 and i'm not smart with computers I have a Windows 7 Toshiba and I got a virus last year and my mom fixed my computer but I think she might have uninstall-ed something that lets your computer install games or something similar to it. I have bought all of my Sims 2 games. I have not downloaded any illegal knock offs of the Sims 2 games. What's wrong and how do I fix it?