We have been using a system based on the hard disk's serial number to stop the program from working on non-authorized computers; in Windows 7, this system fails miserably. It took me a while to figure this out, but it seems that this is on purpose: the Windows function that is supposed to return the hard disk's serial number fails, due to privacy concerns.

Is there any way around this? For example, I might request administrative permissions for the program - although right now, I don't know how. Also, this verification would have to be done every time the program starts, and it would be quite a hassle for the user to authorize the program every time it starts.

We have also considered getting the volume number instead - the information shown with the "vol" command in a DOS window. Once again, I am afraid this might fail if the user doesn't have administrative rights.

The possibility of writing a random value to some obscure Registry key also occurred to me, but once again, I am not sure what sort of access rights this requires.

Or how is this situation normally handled?

TIA,

Hilmar.