Actually, what it is, is an Alcohol-specific problem. A Google search of the forums turned up loads of varying issues in XP and 2K, ranging from BSOD and OS not loading to smaller issues like this. All of them are specific to the latest version of Alcohol and these drivers. If I disable all virtual drives and leave Alcohol installed, the problem is gone.
I was set to blame Benq until I saw how many similar problems have been reported with this driver.
Finger pointing aside, the question is how to get everyone to play nice together so I don't have to disable all virtual drives to use Benq programs.
The other driver file involved appears to be A347SCSI.sys.
It would be nice if someoune could duplicate the Benq crashes with Win2kSP4 and Alcohol virtual drives running. I'm told that the Benq utilities can also crash with some other types of SCSI-based drivers, like controller cards. So it's hard to say what's up, but unless I'm mistaken, the latest version of this driver is the only one that causes it.
So I guess that begs the question of whether a different Alcohol driver could be rigged, or a fix for the current one.