Please check the settings of:
QUOTE
Windows Registry Editor Version 5.00
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\ISODrive\Parameters]
"AutoMount"=dword:00000001
PS: If UAC is not turned off on Windows Vista/7, please right click on desktop icon of UltraISO, choose 'Run as administrator' from popup menu, then press F6 to mount an ISO image.