Try Booting into Safe mode and delete the movie sample from there.
1.Start the computer. The computer begins processing a set of instructions known as the Basic Input/Output System (BIOS). What is displayed depends on the BIOS manufacturer. Some computers display a progress bar that refers to the word BIOS, while others may not display any indication that this process is happening.
2. As soon as the BIOS has finished loading, begin tapping the F8 key on your keyboard. Continue to do so until the Windows Advanced Options menu appears.
NOTE: If you begin tapping the F8 key too soon, some computers will generate a "keyboard error" message. Please restart and try again.
3. Using the arrow keys on the keyboard, scroll to and select the Safe mode menu item, and then press Enter.
It may bethat Media player is stuck in a loop with this file.
If it doesnt sort it post back.