Operating System Troubleshoot

Hi!!
I have a small problem with my Operating System i.e. Microsoft Windows Xp professional.
"In My Computer, Whenever I Double Click any of the drive,
Instead of browsing the drive and error message pops up...
Windows cannot find 'copy.exe'. make sure you typed the name correctly, and then try again. To search for a file, click Start button, and then click Search."


Please Reply on my mail: pratham_tawde"@"yahoo.co.in.
Thanking You...