Whenever I try to open explorer.exe or My Computer

Whenever I try to open explorer.exe, My Computer, Control Panel, or any of the related things, my computer pops up a box with this error:

C:\ it says: Runtime Error! Program: C:\Windows\explorer.exe This application has requested the Runtime to terminate it in an unusual way Please contact this application's support team for more information.

Any ideas on what it might be and how I can fix it? Thanks..

Is this a new problem? Were things working OK previously? Any new hardware and or software?

If this is a new problem try a System Restore to a point prior to the problem:

start > All Programs > Accessories > System Tools > System Restore