Computer won't work

So the past week I've had problems with my PC, last Monday my computer decided to break. The computer would still turn on but my keyboard wouldn't turn on it's lights nor would I get video input(it probably wasn't booting), so I decided to replace the motherboard, same result. I returned the motherboard and got a PSU today which again gives the same result. Although this time it won't turn on, it turns on sometimes but not often. I've tried to power it up manually by putting a screwdriver in the pins, but it still wouldn't work. Once it flashed up for about 0.3 seconds and turned off, that's the last time I could get it working, I have no idea what it could be anymore.

I'll leave it at note that my dad had turned off the electricity and turned it back on when I was in school, maybe that could have been the cause of it? I'm not really sure and I wouldn't count on it because Corsair says on their website that my PSU has protection against strong electricity, also it has happened 3 or 4 times without having any problems(force shutdown by cutting the electricity), so I'm really out of ideas.

I'm sorry for the bad English in this post, it's because I'm in a hurry right now. Anyways I hope you guys can help me figure out what the problem is before I start to pull my hair off.

I don't quite get it. But if I do, my motherboards doesn't make any beeps or anything.

As Roland said, you have to isolate the problems.
Is your energy outlet grounded?
I would say it's a memory fault.
As you already tried a new MB and PS, lets try this:
Take the PS cord out of the PS and wait 1/2 minute to capacitors discharge.
Then take EVERY thing from the MB leaving the CPU. Memory, disks, GPU etc No need to take USB, front panel, speaker, keyboard and other cables.
Try to boot. You should hear 3 beeps from the speaker (out of memory).
Take the PS cord out of the PS and wait 1/2 minute to capacitors discharge and place the memory.
Try to boot. You should hear 1 beep from the speaker.
Shut down and place the GPU (graphics). Try to boot. You should hear 1 beep from the speaker and a message: No operating system.
Shut down and place the C: drive. Try to boot. You should hear 1 beep from the speaker and boot windows.

I tried doing that, but again the power button. I'm done with this computer so I'm taking it to the computer repair shop, I feel like I shouldn't bother doing anything with it anymore. Thanks for all the help guys!