When I turn off User Account, on reboot I get an error message
"Cannot open data file to run registration program"
How can I eliminate this message?

I think he means UAC.

Some programs have different settings in UAC enabled and UAC disabled mode, so that's probably it. Why not set UAC to quiet mode using TweakUAC?

(Another way to deal with this problem without going into the registry)

I recently bought a Toshiba Portege (A600) laptop, running Windows Vista Ultimate, and had a similar problem. I ran Windows Defender, clicked "Tools" and then "Software Explorer."

I discovered a program by DataLode, Inc. called RealConnect Agent, with a startup value of "C:\Program Files\Toshiba Registration\Registration.exe ". This looked like a possible target, so I navigated over to that folder and clicked on the "Registration.exe" file. The same error message appeared. Aha!

Back in Windows Defender, I removed the program from the Startup Programs by clicking the "Remove" button.

I then closed Windows Defender and rebooted.

Problem solved. :-)