Hi, first time poster, but long time techie.
I have an HP 864N desktop system that has been my workhorse since I purchased refurbished from TigerDirect 4 years ago. I use it for literally everything - web design, coding, CD and DVD mastering, video and audio editing, etc.
Unfortunately...it's deader than a Monty Python parrot.
Here's what I've done to troubleshoot the issue.
A. The problem first developed months ago with an alert that the CPU fan was non-functional. Purchase a replacement CPU fan...boot up...get same error. Having just taken my A+ cert last year, figured it was the power supply (not the first time I've had a PS issue, but a first for this box).
B. Replace the 200 watt OEM PS with a 400 watt non-OEM PS...this gets the box going again for next several months. Box is now out of warranty from TD, as well as past the 2yr extended warranty I purchased
C. Start having issues with the system not wanting to power on when the on/off button is pressed.
D. Pop the box open, remove the front fascia, check all wire connections, reseating, and checking each leg of the two power button wires for continuity from button to motherboard.
E. Picked up an Antec ATX power supply checker (http://www.twenga.co.uk/prices-ATX-Power-Supply-Tester-ANTEC-Various-computer-accessories-448770-0) and the new power supply tests out fine, as well as two PS I've taken out of older boxes (but which won't fit the 864N case) so I'm comfortable in saying the new PS is working fine.
F. Replace the tiny momentary-on switch with a couple of different MO switches, to no avail. Box still dead.
G. Last part of the puzzle before going to MB, I replace the AC cord adapter, Trying several different cables of all ages. Dig into my parts stash, and find a never used AC cable. Plug it on. Try one last time...IT BOOTS!.
H. Box stays on for a few weeks, letting me get a lot of work done. Only power down a couple times, and hot reboot a couple of times a day (sadly).
I. Finally, last power off after a long day of use. Next morning completely dead again. No boot. Try AC cables, switch check, continuity check for red/black wires from switch to motherboard...still good. PS checked again...still passes.
J. Lastly, another google of dead machines, brings me here to this forum. I now think the motherboard is the problem. I know it can be replaced, and that's fine, and cheaper than a new box...for now.
So, have I missed anything? Any concurrance on the MB being the issue?
Any ideas or suggestions appreciated.