Computer won't power on after shut down. A conundrum.

Entdroid

Honorable
Nov 16, 2015
5
0
10,510
Hey there guys, I have been struggling with a PC problem for for about a week now and it got fixed a few days ago and now the problem started again. So this all started about a week ago when I installed a thermostat for the house. Like anyone else I shut down my computer and did it. I had to shut down power to the house. Now please note that I do have a surge protector but I didn't not turn off the manual switch of my power supply. So now, I installed the thermostat no problem. Restore power to my house and every thing is normal. Now for all I know, me shutting off power to the house has nothing to do with this problem but I want to include every possible detail.

Now I start up my computer and the only thing showing is the background and icons, no task bar or Windows fully loading. Weird. CAD doesn't do anything. This is probably an important thing right here, I force shut it down via power button. Okay do it again, same problem. This time my idea would be to boot into safe mode and do a slight system restore. But nothing. I'm pressing the power button. Nothing.

I turn off the switch in the back and turn it back on. Nothing. Unplug for a minute. Nothing. I take out every piece of hardware, piece my piece, nothing. My first thought maybe I messed it up because of me shutting down the house power but it turned on after. And if I messed it up, how does holding the power button do that? I give up go to work and I kept trying. This time I turned the switch on the power supply, back and forth. It turned on after 20 tries. Working normally but my windows became non genuine for some reason. I turned it off to see if it will turn on again. Nothing.

I thought maybe I fucked up the power supply. Tried my friends power supply, same problem. Brought a new mobo and tried that too, turned on 2 times, after that nothing. I am pulling my hair out trying to figure this problem out. A day passes, I beg my PC gaming friend to come over and take a look. I probably didn't touch it for a day. And it's working fine. Starts, restarts, shut down, start up. I'm baffled but reliefed. I return the mobo I brought. I brought a new case because why not and my old case was old and dirty. Kinda like doing a clean build again. Been working fine these past 2 days then I shut it down this morning to do a clean windows install and nothing.

Someone please explain to me what's going on because this is so beyond me now, I just don't know anymore.
 
Solution
If the computer perform normally if it manages to boot up then the obvious suspect would be a faulty power supply

You can test this by loading a game or running unigine heaven benchmarks

plaintuts

Admirable
So to summarize..

The computer is now on a new case.
You changed the motherboard but same thing happened so you switched back to the old one.

After a shutdown, it wont turn back on?
And if does manage to power on, how long did it take after the shutdown?
 

Entdroid

Honorable
Nov 16, 2015
5
0
10,510
Windows 7
Asus Z87 Plus Mobo
Intel 4670k
Seasonic G series 750 watt
2x4GB Corsair Vengeance LP DDR3 ram.
EVGA GTX 660 graphic card

Yes he has the same wattage. Don't know the model but he claims it is 750. As I helped him build his computer, I did suggest a 750 watt or higher