My computer is a Gateway with an Intel corei5 cpu, 8 - 12 GB DDR3 RAM (changes during the story), running Windows 7 and then 10 (also changes during the story). Outside of this problem, it had slightly less memory than I needed (which I fixed) but otherwise has never given me a problem in the three years I've owned it.
Okay, so here's my problem: I moved to a new place about a month and a half ago and since the move, I've had this problem. My computer sometimes won't turn on. Sometimes it does, and when it does it works perfectly without any problems at all. But sometimes when I hit the power button, the heat sink fans turn on briefly, but there's no other signs of life. It will, once on, reboot through the software and it never turns itself off or loses power (and I've left it on for days). However, if it enters sleep mode, sometimes it won't come out of it.
My temporary solution is to set it so that it doesn't enter sleep mode and leave it on all the time, but obviously I want a more permanent solution. Here's what I've tried and had done:
* I tested the power cord, surge protector, and different plugs around the house. No change.
* I gave it a thorough cleaning, fans and all. No change.
* I checked the motherboard for obvious signs of damage. None.
* I ran virus software, cleaned up the hard drive and de-fragged it, upgraded to Win 10 (had been meaning to, and I figured it might help if it were an OS problem). No change.
* Held down the power button (with computer unplugged and no peripherals) and then plugged it in and tired to turn it on. No change.
* I checked all the power supply cords were firmly plugged into the motherboard. No change.
* I sent it to the shop, and here's where it get weird. It never gave them any trouble. It turned on and off and went in and out of sleep mode, and generally behaved beautifully.
* They ran a full hardware diagnostic, and more virus scans. No problems found. They installed the other 4 GB of memory, as well.
It turned on just fine when it came back. Stayed on for two days without an issue, and now won't turn back on.
So far my theories are:
* The power supply is only partially working and needs to be replaced. (If it was working when they ran the diagnostic, would it have shown up as a problem? It never shuts off or loses power once it's on, though. Plus, when I plug the cord into the power supply, the fans kick on for a moment, so it seems some power is reaching the motherboard, right?)
* There's some kind of problem between the power button and the motherboard. (But here, it didn't give the techs any trouble, and power seems to reach the motherboard, since the fans turn on for a moment.)
* My house is seriously haunted and my computer is the only one (out of three) that the ghost doesn't like.