They have always worked!! What would this test show??

The voltage off the power lead to the DVD was 5.1V

Thanks for your help. I bought a new MAC. It seemed as if...possibly a motherboard...possibly a hard drive....by the time I got it up and running..too expensive. Therefore. I utilized that logic and bought me a new one. I did however invest in a good battery back up with software shut down features.

Your welcome, you bought a new MAC.

If you can restore your pc it is better you have MAC and that PC.
try also to check the memory replace another type of memory I don't know if your memory is PC100 PC133 PC333MHZ etc...

last time I encountered that type of problem the problem is the Main Switch. Once you press the Main Switch stuck. Pressing the Main Switch for 5 seconds above will shutdown your pc.

try to replace the cmos battery.

if you have the spare CPU/PROCESSOR try to test also remove your Processor from the motherboard and replace by another processor.