The fix is a good cleaning and a check/refresh of the heatsink compound. Here's one video about the work -> http://reviews.cnet.com/Clean_up_your_laptop/4660-10165_7-6648292.html
Today I suggest dumping these disasters on Ebay.
During playback of video, my computer will power off without warning and at random intervals. No "shutdown" screen or anything. Like the power cable is pulled and the battery is out. And when I restart my laptop, there is no message saying that "windows has recovered from a serious error" or anything. Like it never happened. All other functions seem to work fine and no viruses are detected. The problem seems to reside with anything video (i.e. streaming from web, media player, win dvd, encoding video to other formats, etc). Please help! This is extremely aggravating. I have an HP Pavilion ZD8000 series notebook with Pentium 4 HT Processor and ATI Graphics card. I am running Windows XP Home Edition with SP2.