explorer exe not running correctly crashing

Hello everyone. I need some help. I just installed the windows Vista Beta 2 yesterday and I have been having trouble with explorer.exe. I was transfering files around when suddenly in the middle of my moving stuff the computer locked up. I did the usually ctrl-alt-del and stopped the program that was causing it. But then suddenly explorer.exe gave me an error. A windows box popped up saying explorer.exe has stopped working for some unknown reason. Trying to fix problem. Now the box would disappear the screen would flicker and the box would pop up again. Every single time. I restarted multiple times. Did a full shut down and pulled the power backs and nothing worked. I can't seem to figure it out. Right now I am running everything through task manager using it to start programs. But I would appreciate some help if anyone knows how to fix this weird problem. Thanks all. If you need anymore info just ask