I'm new to the forum, and i can't find a PLACE to post my question. it's a hardward problem, but of the minor, and therefore "other" category???
i push power-on sw. for computer, and it turns on [i see the fans come on], but within seconds it turns off, before the monitor can illuminate. i do this two or three times, sometimes turning the main I/O switch off. sometimes the single beep sounds.
SOMEHOW after "X" number of these combinations of I/O switching with pushing of pwr sw the power manages to stay on long enough that the monitor lights up, and all is well.
I am only guessing at this, but maybe i've got the pwr sw installed on wrong pins?
but i can't find a wiring diagram for this mobo; can't find its BRAND and model i mean. this is an old and fine unit. USING Athlon 700mHz cpu, 3 dimms of 256MB each; ethernet from router. just installed new 160GB HD.
even weirder is: i have another pc that i've been hacking around on, switching out power supplies and cleaning fans, and it suddenly started having this same kind of failure--i power on, and it starts just long enough to 'fail'. ouch, i hate that.
can't find any problems at all with surge protector or any 110 V. problems.
most important, tho--when the first mentioned problem pc is running, it is magnificent--i'm reinstalling the OS including security and virus stuff anew,. So it has to reboot, occasionally, and it always does so successfully; and the machine stays running.

the second machine isn't at issue, in my QUERY here.
thanks for pointers.
hispanosuiza