Use Regedt32 to navigate to:

HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Winlogon

Double-click the allocatedasd value name in the right-hand pane and set one of the following:

0   Only administrators of the computer.

1   Only administrators and power users.

2   Only administrators and the local current user.

NOTE: See tip 0237 for allocatecdroms and allocatefloppies.