PSU issues?

[NateDawg]

Alright, fellow Technibblers...I have another one for you. I believe I may solved, but I would like your opinions. I have a client who has a computer that is used as a DVR for his security cameras. About two weeks ago, the PC would turn on. I picked it and verified that the switch will not turn it on. I tested the PSU (it is fine) and I tested the switch (by shorting two pins on MoBo for on/off switch and it is fine). When I hit the switch, it act like it is powering up, but then shut down. I tried different cords..same issues. I made sure all the RAM and video are secures. After plugging and unplugging PSU several times, the computer boots up. I was shocked. After several times booting it up, it still boots up. I am not sure what I did to make it work.

Any suggestions what may have happened, because I am clueless? Could the hard drive prevent prevent system from booting up (like there is no power)?

Thanks in advance for your input.

[Styxbound]

Maybe I just don't know enough, but I've fixed so many machines by now just doing random guesses with things like replugging, clearing the bios, re-seating or changing ram and cards, or even just taking everything off and letting the machine sit a couple of days, I just put it down to the general freakiness of these damn-fool machines. I had a dell a year or so ago that wouldn't start up; had tried all of the above 2 or 3 times and was finally out of ideas. Tried one last time to hit the power button and just walked off and left it. Five or ten minutes it suddenly came on. After that it never gave me any more trouble. So from my viewpoint a lot of these things just have to remain beyond explaination.

[DarDar]

It might have been a capacitor that wasn't fully discharged that was stopping it. When you got it to come on it might have caused it to empty. Or a stuck relay maybe that was connected to the power switch. Now i think about it, the stuck relay sounds more plausible.