This is a handy little program.

It allows you to do "snapshots" of your registry, your drive, or both to detect changes in files or registry keys. It also allows real-time monitoring.

It is not perfect, however. When using the real-time registry monitor, an error popped up that seemed pretty tame, but in reality it was so severe it crashed my system. I'd tell you what the exact error was, but I'm afraid of crashing it again.