Write this down as it is applicable for all your dll's. Sometimes they can become unregistered and need to be reregistered. To do this is quite simple. go>start\run and type in regsvr32 shell32.dll and hit enter. Be sure to put the space in after the regsvr32 and before the shell32.dll
Now if you or the system are unable to find the shell32.dll then it can be downloaded here
http://www.dll-files.com/dllindex/dll-files.shtml?shell32
The download link is just under the " Get help by computer technicians " box.
You will then have to place it in your c:\Windows\System32 folder then use the regsvr32 shell32.dll function. Good luck. }:~)