Restarts randomly... so random that I'm lost

[b3rt_d4ni3l]

Hey Guys,

I need your help with this. My computer recent been acting like a jerk
Restarting randomly when I am in the middle of a game or sometimes a movie... Sometimes even during idle, it will restart...

Now, I have read a few of other thread regarding random restart, most of them is due to heat. So after reading that, I opened up my comp and do some cleaning (wipe the dust away, didn't have a can of air at that time). It was working fine for about 2-3 weeks then it started again. I looked inside, it still looks clean so dust clogging is definitely out...

Lately, coming from a cold boot (power on after 3 days being OFF) it would restart itself during POST...
Even worse, it wouldn't even do anything when I pressed on power button occasionally.

In all this, sometimes I hear a single beep sometimes I hear nothing...

What do you think?
PSU dying? I only had this comp for ~1 year
Overheating? the max temp I've seen is 50C but it didn't restart so I thought thats fine

Help me guys... I am that close to beating the capacitors out of this comp...

EDIT: the PSU I have is below in my sig, it should be a pretty good PSU... Also, my comp is not OC'ed

 

[Okedokey]

Bench test your machine with only essential components.

Test the memory (individually) with Memtest.

Test the 12V rails with a multimeter to ensure they conform to ATX standards or borrow a new one to try (your psu should be fine though in terms of capacity).

 

[GSAV55]

Check the wires that connect the power switch to your MOBO, look where it meets the MOBO and where it meets the switch, same with the restart wire. Also look at your CPU and make sure that thermal paste didnt ooze out into your socket or caps or anything. And definitely check out the rails with a multimeter. Also, check your hardrive for errors, its a utility built into windows if you right click your drive under my computer.

 

[b3rt_d4ni3l]

It was working fine until one day it started to do this...

I thought it was due to some loose cables or some components unseated so I opened the case and made sure that everything is seated fine... Thats when I saw that there was some dust accumulated around the cables and parts... So I cleaned them up...

It worked fine for about 2-3 weeks so I thought thats the problem, but recently its back again...

Is this a symptom of PSU dying??

 

[GSAV55]

Try out the stuff that bigfella and I told you to do and that will narrow down the possibilities