I think this is the registry entry that is causing the trouble
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\RunOnce\"autorun" = "autorun.exe"
Delete the entry "autorun"
and
HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon\"Userinit" = "userinit.exe,autorun.bat"
In this edit the entry "userinit" and remove autorun.bat..