From this state, I can hit the reset button and the white screen will go away, showing the full desktop in in the middle of shutdown procedures.
The problem occurs in safe mode, too. In this mode, the system will reboot when the virus asserts itself.
I have been able to get a stable system when I start in safe mode with command prompt.
I was once able to start up in safe mode and disable startup and system services, which I thought stopped the bad behavior. In this state I was able to run a scan with the installed PCTools Spyware Doctor with Antivirus. It found some low risk cookies, but nothing significant. I cleaned up some unneeded software and restarted the system in full startup mode.
I have also connected the hard drive to another system as a secondary drive and run a PCTools scan. It found nothing.
The problem continues.
I did get an error message once that a program performed an illegal instruction. The program was in my users temp directory and was called 1.txt. It looked like this filename was being dynamically generated.
Any help you can give me to figure out what's happening will be appreciated.