I notice that this is by far one of the most comment problems people are having. So I've merged a bunch of threads on this subject into one and it is sticky'd for now.

So for this issue please do not start a new thread, but instead post here if you are getting the "Windows Vista has stopped working." error message frequently.

Also here is the Microsoft Knowledgebase article for this problem, which doesn't have much info but may be useful to someone:

Error message when you log on to Windows Vista: "Windows Explorer has stopped working"

Thank you!