My Documents open on startup

Everytime my friend's computer boots up, My Documents opens up.

 

Its happened because "Explorer.exe" may have gotten affected, or the original path has been changed?, once your computer has booted up, and your my documents has loaded, To solve this problem follow these steps.

1.  Goto Start -> All Program -> Run
2. Type "Regedit" in the Run window then goto: HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon
3. Then look for a string called "Shell" double click then another dialog should open, in the field "Value Data" type "Explorer.exe".
4. Restart your computer.