help diagnosing a problem

[Mathematics]

story:
this may or may not having something to do with it but...got windows 8 for free from uni so i decided to install it. first time i installed it didnt work, errors and whatnot. second time it did. come home from uni for thanksgiving break and i hook up my pc.
my pc randomly loses power and wont boot back up. turning off power, unplugging, replugging everything...computer just will not boot up. my mobo wont even beep anymore.

SO..i troubleshoot as much as i know how. put harddrive in brothers pc..hdd is fine.
im like 99.9% sure that my gfx card is not the problem.
took battery out of mobo and reseated it. didnt fix it.
decided to format my hdd via my brothers computer to see if maybe windows 8 was in some kind of weird sleep mode that it wont come out of. that didnt work.
opened brand new pin connectors and tried those. still doesnt work.
reseated all ram, tried to start. put only one stick in, tried to start. both didnt work

so basicaly, my computer fans and everything turn on, but no beep and nothing appearing at all on screen.

could it be my cpu or mobo? if so how would i go about troubleshooting those two things?

[Jintu]

Use your brothers psu in your pc or put yours in his and see if anything changes. If nothing does, I'd bet a mobo issue. When you attempt to boot up, is your keyboard getting power/notice caps lock/num light up?

[Mathematics]

Use your brothers psu in your pc or put yours in his and see if anything changes. If nothing does, I'd bet a mobo issue. When you attempt to boot up, is your keyboard getting power/notice caps lock/num light up?

my keyboard locks arent lighting up, but my mouse is lighting up (i have a razer which lights up blue). but yeah my keyboard isnt lighting up at all. i wouldnt be able to switch power supplies with my brother so thats out of the question

[Niya]

Hm... Just fans and no beeps means the system doesn't even reach POST... Try it with no RAM at all, that would normally trigger a beep code. If still nothing happens, most likely your MB or CPU is fried. And other that putting the CPU on another MB, there's no real way to test it...

[Buffy]

If it doesn't beep, it doesn't POST. You can visually inspect the CPU for damage, but I'd bet money on your MB.

[Mathematics]

thanks for the help guys. judging by what you guys are saying it has to be either the mobo or cpu. i need to upgrade anyways so at least now i have an excuse to finally get a quad core >.> and a mobo that supports one

[Crowort]

My money would be on PSU until proven otherwise. They just tend to die the most out of the things you have listed.