Your computer's Path statement got messed up.
To check it open a Command Prompt and type: Set <hit Enter>
and check whether the bellow path is available
Path C:\WINDOWS\system32
If not you have to edit your path in a way to access the c:\windows\system32
To edit the Path to correct it select Start, right click My Computer, select Properties. Next select the Advance tab, and Environment Variables button, and select the Path variaile listed under System Variables.
When editing it should include:
%SystemRoot%\system32
Which translates to something like:
C:\WINDOWS\system32
Each entry included in the path must be seperated by a semicolon.