Visat 64 Bit Switch Users Computer Freezes

The computer is less than 2 months old. We have four Users accounts set up on the computer and they are all setup as Administrators. When we switch between users the computer freezes up. The computer screen goes blank and a "NO SIGNAL" comes on the screen. I have to press the power button and the computer shuts down and then I can restart it. It happens every time. If I select the Start button then "Switch Users" it will go to the user I select but when I try to switch back the computers freezes, no mouse, no cursor, no key board, it flashes No Signal and then just a blank screen.

I have restored windows to earlier configurations, I have researched the problem on the internet through Google, I have gone to Microsoft's web site and searched for the answer and I have contacted Gateway and they had no idea. I created a Recovery Disk, backup all my settings and files, installed the recovery Disk and restored all the backup files, reinstalled all the programs and I still have the same problem.