How do I force a delete of NTUSER.dat?

Clarifications

maybe try going to dos shell....navagaiting to folder where file is, do an attrib -? for information and change attributes of the file to make it deletable (then delete in dos)....

I know this seems obvious, but is the user logged in? That would lock the file.

If you can't get it deleted, it may be time for an alternate path, such as booting another OS and mounting the drive as data to do the cleanup.

WARNING - ANY time you mess with the registry, you're running the risk of making the system unbootable. and NTUSER.DAT is part of the registry, so deleting it improperly could "brick" the system.

No, the user is not logged in and has been deleted from Active Directory some time ago. Yet his profile remains on the machine and to free space on its relatively small hard drive, I need to delete the folder.

attrib was not able to change the attributes on this file.

One more thing. This isn't the only profile on the machine. There are many. I'd rather not have to make changes to each ntuser.dat for each folder.

User Profile Hive Cleanup Service

http://tinyurl.com/26dd9so

from Windows explorer? If so you can run into trouble, this is the correct way to delete profiles;
http://www.microsoft.com/resources/documentation/windows/xp/all/proddocs/en-us/sysdm_userprofile_delete.mspx?mfr=true