Why won't these MPEGs play properly?

I have a small collection of videos in MPEG format that someone else has created. I don’t know how they made they videos but they did a bad job. So the videos will play in Windows Media Player but they cause an odd problem. After playing one of these videos my CPU usage goes up to 99-100% and Windows Media Player refuses to play anything until I ctrl-alt-delete and end task on it. BSPlayer, which will usually play anything at all, encounters the same problem.

As far as I can figure out, this isn’t a codec problem. IIRC, MPEG doesn’t use codecs like AVI does. To my understand, each file should already contain all the info necessary for playback on any Windows system. And according to GSpot, this file can be successfully rendered, which means it should play back smoothly. So I’m lost here. Why are these files playing but then messing up my system?

For reference:
AMD Athalon 2400
512 mb DDR RAM
Radeon 9000 video card with Cat 3.10 drivers
Windows XP Pro
Windows Media Player 8

I’ll post any info from GSpot upon request if it’ll help figure this out. But nothing jumps out at me as being obviously wrong with the files and they do actually play so GSpot is the wrong tool for the job. Ideally I need a program that will tell me what is wrong with these files and how to fix them.

PS: I know someone will say update to Windows Media Player 9. I’ve already updated to WMP9 in the past and doing so doesn’t fix the issue. But if someone has to suggest it, I’ll do it and report the negative right here.

PS2: The videos are fan made videos of the ever beautiful Heather Locklear, if you really must know.

Just bumping my old thread to note that this problem has since been corrected. It was caused by having too many codecs installed.