PC shuts down by Itself.

[wbg34]

I have a Win98 PC (Dell Dimension l1000r) that will shut itself off automatically. It does this at variable times and got to the point where it would not boot at all. No beep codes, no diag lights on the MB, nothing at all. Followed Dells trouble shooting steps and isolated the mother board as the cause of the boot problem. I replaced the mother board and the PC has worked great for 3 days. Today it started to shut down again.
Are there any utilities that I can use to monitor the pc to see what is causing the shutdowns? I tried using Dr. Watson but that didn't pick up anything.

 

[fenix]

You didn't mention checking the power supply, but I would have tried to find the cause of the old m/b going bad. I would do a voltage check, and I sincerely hope that it was not the cause of the old board frying because, well let's not go there....

http://www.thetechboard.com/tutorials/atx.php

 

[CMooreJr]

Have to agree. The power supply is made to shut the system down in case of to much/to little voltage going to the internal components. The good thing is you can pick up a new power supply for $25.00 bucks or so, and they are a breeze to replace. (A little annoying when it comes to the power button, but other than that, pretty easy)