Hi, I've had a few varieties of this general problem for a while now but it's gotten to the point where I'm kind of at a standstill with it.
When I first built my computer everything worked fine. After about a year and a half (just recently), though, I've started to have problems with it. The biggest thing that would happen is that whenever I would try to install something big from CD, the computer would crash after a little while of copying files. It would then restart and boot back up. It was that way for a while, and then it got a little worse... to where when it would crash, the computer would lock up entirely (HD activity light solid on and monitor in standby) to where I would have to unplug it to get it to shut off. When I plugged it back in, sometimes it would boot back up and sometimes it would go back into that locked up state from before I unplugged it.
After a little bit, I noticed that the computer would lock up if I turned it on with a CD in the drive. It wouldn't even POST. When I took the CD out of the drive (generally I'd have to use a needle and manually open the drive to get the CD out), it would boot fine. I'd have no problems until I stuck a CD in the drive, at which time the computer would crash when the computer tried to run autoplay on it. I tried disabling autoplay but it didn't matter because the computer would crash any time anything tried to access the contents of the CD.
I got frustruated with this and did the smart thing (sarcasm :p )... I wasn't thinking, assumed it was an XP problem and wiped my hard drive so I could reinstall XP. Well, I never got XP back on the thing. Whenever I try to boot with a CD in, either the computer won't POST, it will POST but it will freeze when it's detecting the IDE drives, it will POST fine but it won't detect the CD drive at all, or it will (very rarely) make it past the POST with the CD drive detected. However, as soon as it tries to boot from the CD, it's over and the computer restarts. If I boot up without a CD in the drive, it will work perfectly fine. It will get to where it tries to boot from CD and say "Invalid system disk, please insert one and press enter" since there's nothing on my hard drive. When I put a CD in and hit enter, it will crash. Sometimes it will crash with a CD in before I hit enter. Very rarely will it actually start to boot from the CD. Windows XP setup will either crash at the "Setup is detecting your computer's hardware config", or it will load all of the various device drivers at the beginning, get to the first screen of the Windows setup, and then just crash. The only CD that I can sometimes use without crashing is a Windows 98 boot disk on CD, and that will only work if I choose to not load the CD drivers.
Things I have done to try to fix this:
Switched the CD drives (3 different ones)
Switched the IDE cables
Switched my RAM sticks out one by one
Tried a different hard drive
Reseated my processor and heatsink
Switched my graphics card
Removed other cards that aren't needed (i.e. sound card)
Bought a new motherboard and put it in (solved the system locking when it crashed)
I have no idea what is causing this. I've switched everything, it makes no sense. Why would it crash because a bootable CD is in the drive? When I had Windows installed, it wouldn't boot up if the CD in the drive was or wasn't bootable, it didn't matter. Now it seems to not care if the CD isn't bootable. I put a non-bootable CD in when it gave the "Invalid system disk" error, and when I hit enter it didn't crash, just told me again the disk was invalid.
Has anyone heard of this happening before? And more importantly, what's causing it and how do I fix it? O.o