Media players lag entire system w/ some video files

On 2.66GHz CPU, 1.5GB RAM, GeForce 6 series GPU, clean install of Windows XP SP2:

Any media player I try lags my entire system when attempting to play some videos. Initially it would lag the mouse as well as the screen occasionally blinking black for 1/10 of a second until I disabled overlay for media Player 11. Now it sucks up 95%-100% CPU cycles, but at least the GUI is responsive again so it's easier to kill the offending apps. So far it seems only to be WMV format, and some unknown format streaming media that loads through an embedded Windows Media Player (probably WMV as well).

I initially had Windows media player 9, tried uninstalling and upgrading to 11. Tried DivX, RealPlayer, etc. etc. cleaning all previous media player installs with each different installation.

I've tried ACE CodecS Mega Pack as well as K-Lite, and neither fixed the problem. Everything still lags and says "Opening..." when I play certain files.

GSpot reports codecs installed for the files that do play, but for WMV files it only displays file size info, plus the File Type and MIME Type in the "container" list.

I've already tried cleaning and reinstalling graphics drivers as well as trying different versions. Anyone know what else to try? This is hampering some important college work as I need to view some streaming videos. Thanks in advance for any suggestions.

- Jason


Edit: And any media player I use seems to remain resident w/ high CPU usage after it appears to close. Surely this is enough to identify the problem...

Edit 2: Don't you hate it when you can find the exact same problem you're having, but nobody has posted results or working solutions? http://forum.videohelp.com/viewtopic.php?t=309711