chances are there is a fault with you Explorer.exe file,
but try creating a new user and see if it happens, if it doesnt it may be a fault with the user settings, unfortunatly i do not know how to solve that, so just cut n paste all your documents across and delete the old user,
otherwise insure there are no viruses that may be causeing the fault, try AVG and also a scan from Advanced Windows Care2 from Iobit wouldnt go a miss, both are free to use and download,
And if all else failes copy the explorer.exe file from another system running the same version of windows. this is found in C:/Windows/
and is indicated with a icon of a computer, do not copy the one that has an icon of a folder it is not the same thing.
Let me know how you get along : Tastyklean@bluebottle.com
Jonathan Pugh
April 2008