Please open Notepad.
Copy the purple text to a new file.
Save it as repair.reg on your desktop.
change save as to 'all types'.
REGEDIT4
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon]
"Shell"=-
"Shell"="Explorer.exe"
Close Notepad.
Double click repair.reg
When asked if you want to merge with the registry, click YES. Wait for the "merged successfully" prompt.
Reboot the computer. If you see any errormessages please write them down and let me know.