DVDs video and audio rapidly skipping

hey all. I've a Lite-On shw160 and it wont play a dvd smoothly. it just keeps jumping every second. the pc has WinXP 1GB RAM decent GeForce video card. ive tried everything. Firmware update on drive. Latest video card driver.
Tried drive in another pc its works fine. The sound run thro the motherboard cause theres no sound card. but the cpu usage doesnt really increase wen watching the dvd. would it be the sound making it all jump or what?

let me no if anyone has and solutions
thanks

It may be background processes causing high CPU usage when playing
(you didn't actually state what the CPU usage is on)

I usually use Startup Control Panel, and remove most (if not all Startups)
Also you may wish to download CCleaner to remove all those temporary files (causing any machine slowdowns)
One last option would be Memtest on your physical Ram