I have been having the exact same problem recently. Did you mean to say you CAN'T cntl-alt-del out of it? When this happens to me, the only thing I can do is a hard reset. I primarily see this problem with Rogue Spear, but have seen it a few times with CS and UT as well. I'm not sharing any IRQs, either. I have forced my SB Live! X-Gamer to use IRQ5 and it is the only device on that IRQ. I might try moving it to a different slot just to see what happens. The problem is driving me nuts, though. I see it in both Win2k and Win98se on this box. Due to the sound looping, I think this is somehow soundcard related - just not exactly sure what yet.
The only similarities between our systems that I can see is the soundcard (I'm also using liveware 3). I'm running Detonator2 5.32 drivers with my TNT2U.