Can't make SP2 install from CD

Dear Anyone.

I hope this is in the right forum, if not, please accept my apology and move it!

2 interconnected problems. Had to send my comp. to a professional because it got TOTALLY infected with about a zillion viruses, my fault, downloaded a freebie that came complete with a backdoor virus that hung out the red carpet for all its little friends. Thought I'd deleted them but they'd hidden in System Restore....

Got the comp. back with a clean, blank hard drive. Reinstalled Windows, no problem. Then I put my SP2 CD in, it went through the process of loading all the files into memory and.... that was it. It never actually started the INSTALL process. Instead, it just made the little yellow 'hard-drive-active' light come on and stay on forever. Before I had to send the comp. to the expert, the hard drive light would go off if I wasn't doing anything. Now it just stays on all the time.

I'm a little - O.K., a LOT - worried by that - why isn't the drive powering down if I'm not using it? And why isn't SP2 installing after loading all its files in? I want to reinstall AVG, but I have to install SP2 first, so right now I'm relying on Windows Firewall for all my virus protection.

If I restart the comp. now, the 'hard-drive-active' light STILL stays on all the time, even if I'm not doing anything. Please, anyone got any ideas?

Yours hopefully

ulrichburke