I've got the same.
My investigation didn't enlighten me regarding to the solution, but rather ensured me there's something wrong with drivers.
I use SLI since long time, but Win 7 x64 since 6-7 months. I've seen "drivers stopping" message before, but it was always caused by some specific action and was easy to fix (like high GPU temps = lowering temps, old drivers = install new drivers, messy drivers = cleaning the system & reinstall drivers etc). Most of those appeared during intensive GPU usage, like gaming.
I started to suffer this issue couple months ago and unfortunately, I haven't noticed which update caused this (I update players, codecs, drivers when they just release in newer version). Most likely it arose once I've reinstalled nVidia drivers.
In this case (and in my case) drivers stop working & respawn when video action is taken. When I doubleclick on any movie icon - I'm almost sure the drivers will stop responding. It's not any players issue as I've checked plenty of them... I've changed even default player to BestPlayer as it can handle hangups easily, unlike MediaPlayerClassic/HC which requires hard reset. Maybe it's a codec (Shark 7 codecs + x64 components) issue which hangs some driver's component - I have no idea. As far as I remember the same was with K-Lite codecs which I removed and replaced with Shark. But unique is that once drivers stop working & respawn - I'm able to open any movie with no further hangup... until system restart, of course. I have had no such behaviour always - it started couple months ago, as I said. And about one month ago I've noticed the same with some YT movies (Adobe Flash). Never ever I've had it with games - games, benchmarks, temp testers are fine.
Reason why I think they are drivers - under WinXP, or Linux (Mandriva 2010.1 x32, 2010.1 x64, Ubuntu 10.10 beta x64) everything is fine - movies, Flash....
I'm afraid it might be next "memory leak" in x64 Windows 7. Previous "memory leak" made me to sell Audigy card which can't afford microphone support, as most of you probably know (see Audigy & Audigy 2 mic issue with x64 Windows 7 & 4 or more RAM memory).