This isn't something that's obvious to most people, so here's the thing about BSODs and system crashes: They cannot be caused by most applications, including KeyClone. By design of modern computers and operating systems, applications like KeyClone (and even my applications) run at "user level", which is basically (or ideally) shielded from bringing down the whole system. Things that run at "kernel level" (I'm not using the exact technical term here) can interact directly with the hardware, this includes drivers and the operating system itself, and can probably blow up your computer. The main thing that applications can do that affects the whole system is saturate a resource, like your CPU or video card, meaning use it a lot without letting it rest -- in which case the problems would be described as slowness, up to overheating, which could then cause a hardware failure and therefore a BSOD, crash, freeze, etc.

Like Valdemarick said, when you BSOD it actually tells you the name of the driver that failed, for example nv4mini.sys, and that can be googled to help figure out what driver or hardware is causing a problem. If I had to guess, it's probably related to your video card. Try updating your video card driver first, and see if the problem stops. If not, it's either going to be a process of trial and error (updating drivers, replacing hardware that might be going bad, etc) or you might end up getting one of the "windows shut down unexpectedly" boxes that might have some helpful information about what driver or hardware is having trouble. Also since you mentioned sound, you might want to check for sound driver updates as well. If you have a Sound Blaster product (Live, Audigy, etc) their Vista drivers have been notoriously bad.