Well, I turned off all the power management options, and it was fine. So I have it narrowed down to monitor power down, and HD power down. In the meantime I can shut it off manually. Someday down the road I would like to be able to shut off the monitor automatically.

I checked the BIOS, and all power management options are off. Could a program cause a conflict with ACPI? It says that it is ok when I look in device manager at the advanced computer management stuff.

The last ACPI error in the log was last night, probably when the HD and monitor still was powering down. It didn't have trouble coming back, but the log still got an error.

I will try disabling some programs and report any success.