Phil,
I did a google search and found that a program called ACDSee Auto Device
Detector detects when a device is connected to your PC and gives you the
option to acquire images from it automatically. Do you have this software
installed? Perhaps installed when loading some software that came with a
camera you're using? If you do have something along these lines, it would
seem logical that it's causing a problem of some sort, but I have no way of
know what it is. Perhaps it's having some conflict with a Vista component.
Does any of this make any sense to you? If it does, try uninstalling it to
see whether that act takes care of the problem. It's likely that you don't
need it anyway.