Ok... I bought this computer for my dad and brother to use about 2 years ago. Its used for really basic purposes such as browsing the net, using a magic jack on it and a few basic other things. Nothing all that crazy. I came to visit my dad for a few weeks for the holiday period and was sitting there using the computer browsing the net, when it suddenly shut off. I thought hmm ok that was wierd. Turned it back on used it normally. Then it started happening more often, and my first thought was it was over heating but not so, as it can be off for many hours and do the same thing.
After a day or so of that, its new thing to do was to turn on for a few seconds start booting that shut off, most times before even reaching the windows logo. Sometimes it would only stay on for 2-3 seconds. So I opened up the case, cleaned out all the dust from inside of which there was not much. No burst or swollen capacitors on the motherboard. Reseated the RAM had the same problem. I tried a different outlet same problem. Then I turned it on it ran for many many hours, I ran all the hardware tests HP has and they all passed. I ran temp monitors and they were running no higher than 35 degrees C. I shut it down overnight and turned it on in the morning and it ran fine. Shut it down and restarted it several times. That same afternoon, it failed to turn on again.
So.... its main issues are it either turns on runs and then shuts off seemingly at random intervals, ranging from several hours to a few seconds. Some of the times it turns on, there would be no display and the CPU and chasis fan would be off, but the PSU fan would be on. No power to mouse or keyboard.
The only way it would be consistent was when I took out the CMOS battery, and now every time it turns on it would have all 3 fans running, no display, no power to mouse or keyboard. No motherboard beeps at all btw. I took the computer apart thinking I had a spare power supply that would work but it was too small a motherboard connector.
Everything got disconnected and reconnected, all the plugs and connectors except for the CPU. After doing this last set of stuff It ran fine for many hours, then just shut off and did the same thing. I left it unplugged all night, and now here I am posting this on the same computer. What the hell is going on lol.... is it the power supply issue. If so... why so random in its behavior.
By battery I assume you mean the CMOS battery? As it is a desktop. No I have not tried that. After shutting off on me last night I used it this morning with no issues. Using it now been running for 3 hours straight... If it shuts off again which I am most positive it will I will give it a try.
The only thing that Event Viewer reports relative to my problem is Kernel-Power one... saying system lost power unexpectedly. And by "shut off" yes I mean as if it is unplugged from the wall.... a sudden power loss. I don't think its the RAM tho because I have tried both chips seperately in each spot with no luck.. and with no memory in i get the typical motherboard beep.
After unplugging all the power connectors and then reconnecting them a couple days ago it has run for hours on... except for one time when it had sudden power loss, same as before. I left it unplugged overnight and it has been running for 6 hours straight with no issues. I am trying to find another supply to use to test it.. but have not been able to fine one with the right connector.