Why wont sims 2 install?

Okay i need to install the sims 2. When I put in the disk, a little cd icon appears right by the mouse and stays there for like 30 seconds and then it goes away and nothing happens. i go into my disk drive and it is not there. Please help. I have windows xp. The thing that confuses me is I installed the sims 2 on this exact same computer like 6 months ago and it worked perfectly fine. But then we got a virus on it and the hard drive was wiped clean so i need to install it again. Please help i am getting so frustrated.