Thank all of you who have responded to my request for help with a computer that dies, then sleeps for some time before reawakening.  I've tried a number of the suggestions, but have not, as yet, replaced the power supply.  The situation with the machine has not changed.
There is an additional "clue" that I didn't mention earlier.  When the computer is turned off after a freeze-up the indicator light on the monitor changes from green to amber.  When the computer is turned on again, if it's going to boot that light changes back to green almost immediately - if it remains amber then I know that it will not boot and I have some additional waiting to do.
I'm now at the point of thinking of changing out components to see if I can locate a possible bad item.  The easiest thing to change is the video card.  Question: Will any video card work?  Same for the sound card?  Or does it have to be "matched" to the particular computer I have? It can't be the modem board as the problem occurs whether or not I'm using the modem.   The machine is about four or perhaps five years old and I've just read that there is a battery somewhere in the machine and that's never been replaced.  Can a weak or worn out battery be the cause of this repeatedly "dying" problem?  I understand that if I take out the old battery to do the replacement I'll lose some information in the CMOS chip.  How can I replace that info?  I know these are dumb questions, but.....
Thanks again folks,
Lewis Emerson

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