Rundll32 problem

OS: Windows Vista 32 bit
Graphic: Nvidia 8600 GT
Problem: caused by a MPEG file on desktop

Description: okay, this happen when I opened a folder containing some MPEG files. Everytime I open them it gives me a message that says RUNDLL32.exe has encounter an error and shortly after that the Window Explorer restarts...

for some reason, I actually dragged one of the MPEG file to my desktop, now it created some royal pain, instead of going to the folding and getting the message. I get the message everytime on desktop, so basically i cant do anything, and i have to use guest account to send this message. Everytime i enter my admin account, the error window kept popping up, and explorer kept restarting...

I tried to go into my own account, the admin account, in SAFE mode, to delete that annoying MPEG file causing the problem, but that doesnt seem to work.

Can someone please tell me specifically how to solve this problem..
i have an important project due 2morrow...and I appreciate any help and directions given...