So u meant to say its a blank desktop .If its XP follow the below
1)Open Task Manager
2)Then file new task, type regedit.
3)Then go to HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\Image Execution Options\
4)In this list there will be a entry explorer.exe right click on it and export it. then on the right hand side delete the "debugger" key