XP Temporary Freezing

My computer keeps freezing every minute or so. The mouse freezes up, I can't use the keyboard and if I'm listening to anything then it pauses on whatever note it's on for however long it stays frozen. I don't know many technical things but what I can tell you is that I'm running XP Media Center Edition 2005 with a 512MB PC-3200 400 MHz DDR. Intel Pentium 4 Processor 540J with Hyper Threading Technology Processor Speed 3.2 GHz 800 MHz FSB 1 MB L2 Cache.

 

Atapi and Cdrom

Ok I looked into event viewer and it looks like atapi and cdrom are having errors about every minute or so. Does anyone know what I can do about this?

 

I know this is late but thanks for the help TimW I really appreciate it.

My comp is still freezing at times but it's gone down a lot in the past couple of days. I'm going to run through the Malware removal guide again and use that link you gave me. BTW It wasn't doing it in safe mode when I was did the malware removal guide the first time.