windows explorer crashes

Whenever I open my computer or my documents or any such folder, windows explorer crashes with no warning. There is no "windows explorer has encountered a problem", just explorer closing down and sometimes rebooting. This also happens when I open internet explorer. I've turned off third party extension files but they don't seem to be the problem.

I've also scanned my computer with spy-bot search and destroy and pc doctor and neither detected and trojans on my computer.

I've also turned off DEP which seemed to be causing many vista users a similar problem, but it still doesn't work. Any advice? I have no clue what else I could do. Any help is appreciated.