PC turns on but doens't boot or registers connected screen, keyboard and mouse

[dardarland.gaming]

Hi everyone,

So... this is my problem. When I try to turn on my PC all fans spin and all lights turn on from all PC components, but it doesn't boot and doesn't give a beep. Also my screen, keyboard and mouse aren't being detected.
I'm sure the GPU, HDD, and RAM sticks work (I tested those components on another set up).
I removed the RAM sticks to see if the system would give a beep (as an indicator that the memory is missing). It beeped.

I tried some different things to see if I could fix the problem. Here is a list with the things I tried:
- removing the power cord and hold the power on button for 30 - 60 seconds;
- cleaning the RAM slots with air;
- cleaned RAM sticks with alcohol;
- tried every RAM stick in every slot (one by one);
- reconnected every component;
- swapped out the old battery on the motherboard for a new one;
- CMOS reset;
- BIOS reset;
(I maybe forgot to mention a thing or two, but this is what I remember right now).

Here's the backstory. This problem is not about a new build. This pc is made out of left over parts from a friend of mine. At first it worked. I was just playing a game. After a couple of hours I got tired so I stopped playing and turned off the pc (just in a normal way). After two hours I tried to turn on the pc again but it wouldn't boot.

Basic info PC:
- Asus P6T Deluxe V2 (motherboard);
- Intel i7 920 (CPU);
- Corsair Dominator 2048MB DDR3 6GB (3x 2GB RAM);
- Asus GTX 660 ti (GPU);
- Corsair CX430M (power supply).

 

[arif1752002m4a1]

Check your PC with new and good and more powerful PSU like 550 watt. (check at least) because I also faced such problem.

And use another graphics card too (for check that is it's ports are OK or not)