Hard Drive and/or RW Drive constantly on

I am currently running Windows XP. I have an unusual problem where the CD RW Drive will turn on when there isn’t a disk inside, and eventually leads to my system running very slow or stops. I have disconnected it from the control panel to see if there was a fault with the drive. After awhile, my hard drive lights up for no reason and stays on, then hangs my system.

It appears that it does it after the PC has been running for awhile. I have no viruses on my machine and it is well ventilated. I am wondering if maybe there is some form of heat build up inside. I have cleaned the inside of the case, and I have checked all programs running in the background and everything is working correctly. What else could I check?

Thank you…