trouble with [intermittent] shutting down [and restarting]

Kazz - Welcome to WindowsBBS

I think you have two separate issues here - the intermittent shutdown and the unknown device.

As far as the latter is concerned have you noticed any lack of functionality - is everything working as you would expect? First check in Device Manager if any drivers are installed for the unknown device (unlikely) and then disable it and reboot. This should prevent the Add New Hardware Wizard from popping up. If you have noted a lack of functionality - loss of sound, dead modem for example post back with details.

Since you have set the computer not to restart on System failure does the computer shut down to a blue screen with a stop error listed? If so what is the error?

If you do not see a blue screen the problem may be hardware related - overtemperature, faulty power supply (PSU) .....

Let's see some temps after the computer has been on a while.

Download and run Everest
Under Computer > Sensor there are a series of temp/voltage readouts - post these.

Also check in Event Viewer for any events flagged in red or yellow at the time the computer shut down.

 

What happened to the temperatures/voltages data I requested?

Can you be more specific regarding the BIOS error - is this a message on the screen or a series of beeps on boot?

It may be that the CMOS battery on the motherboard requires replacing.

I was referring to the power supply unit (PSU) in the computer.

If this problem occurred immediately after you moved house, i.e. transported the computer to a new location, it is possible that a knock or vibration has dislodged or loosened a connection. Go inside the case and unplug each cable one by one and replace and see if the problem is resolved. While you are in the case you will see the CMOS battery in a holder on the motherboard - it is a button battery about the size of a large coin.