Dear There Are Multiple Of Reason For That.
The Common One Is Virus Which Attached In Start-up-Items On YOur PC And Affect It.
Or May Be It Is Due To Terminating The Critical Process Like csrss.exe Or svchost.exe In OS From Task Manager.

Hope You Get It?
If Not Post Me!

It might be due to HEAT in the tower,that causes reboots....

Try cleaning inside around all fans,etc and see if it continues!

Welcome to daniweb

Look in Event Viewer/System/application for possible clues.

Dear Rleeq!
This usuallu happens due to virus which arrived almost a year ago but that's not the only reason for that it can be caused by the error in some hardware especially ram try changing your ram or try defragmenting your hard drive also make sure that if some has set a timer that automatically turns off your matchine..

Hi there,

So you said that you are getting a warning, hmm, that sounds familiar. Try the following (at your own risk):

Try this command just to chek if this is the same warning that your getting before the shutdown.

shutdown /s
Then hit enter.
This will cause the system to shut down.
Then use the same command but use the /a swith intead:
shutdown /a
Then hit enter, this will prevent the system from shuting down.

Please let me know if that is the same warning MSG

Best regards and good luck!

I think it might be over heat. I do have a machine with these synthom

If you get this message you must fast double click on your clock in taskbar and change set some previous date or just move back one hour to get some time to see what is happening

Open Control Panel, In the Control Panel double click System. then go the system Properties window, click on the Advanced tab. Locate the Startup and Recovery area and click on the Settings button.
In the Startup and Recovery window, locate and uncheck the check box next to Automatically restart.
clcik k twice. now when the system shuts down you will get a BSOD it will tell you the error. However, if you are getting the message in this picture then you have a trojan/virus/malware

Thanks for all the suggestions/ideas.
BobbyRaw...That is the exact message I am getting.
I don't know if it is significant but in the second part of the message it says:

"Robot initiated by Allair ClusterCats IP Alias Daemon due to an IP Address Conflict."

Because the shut down happens so quickly I can not access the even control panel to do as you suggested.
So this begs the question; If it is a Trojan/virus or such and the system shuts down so quickly, how do I do to get the virus of the machine? Is there a software that will run from disk which will load immediately on reboot? If so what is it please and where can I get a copy.