It definitely seems to be resource related, but I can't monitor CPU usage because everything freezes up, including any monitoring utilities. Even when I get the task manager up, I have only a couple seconds before that freezes too to click End Task on Media Player... and it usually takes several tries.

And yes, I have HT enabled. The CPU graph for one logical processor spikes to 100% and then everything freezes (instantly) so I can't see what happens next.

Also, it doesn't matter what file I play or whether it is a preview. Even a lousy 1MB 16 second AVI freezes up the whole system if Limewire is running (just running, no uploads or downloads or even searches). If Limewire isn't running, the file plays fine.