dvd jitters

I'm gonna try this question again; the first round didn't get to the problem.

I have a Toshiba laptop (Tecra 8000) with cd-rom/dvd drive.

When my brother gave me the infernal machine, it played dvd's fine.

But, since I'm using it for school and have internet access, I found out quickly that I needed things like firewalls, antivirus, etc.

Got McAfee, ZoneAlarm, Spyware Blaster. The dvd got the jitters--really a fairly constant glitching of sound and sometimes video--usually when the drive light is on.

So, I shut off or removed the protection softwares, but the drive still glitches.

Went so far as to reinstall OS (Win 2K) and the dvd decoder only; still glitches.
Task manager shows plenty of memory during dvd playback, but the CPU tops out regularly at 100%.

Any suggestions?

 

sounds like the drive is busted ... try a known working one

 

Not sure about the "busted" thing, because the drive plays CD's flawlessly, and significant portions of some dvd's fairly cleary. The glitch is an intermitant but consistent problem. I'm mostly wondering about the CPU at 100% symptom