desktop not show

Hi,

After I used Norton Antivirus to delete SMSSU.exe virus and reboot the PC,
the desktop (icons and Start button) does not appear. I reinstalled the XP
pro and it is no use. Are there entries in Register to dispaly desktop? I can access task manager and cmd. When I run explorer.exe, it says "Windows cannot find 'C:\windows\explorer.exe' ". But it can run other apps such as
notepad.exe.


Thanks.