Question Is the motherboard dead or is it the CPU?

[SamHamm]

Hello everyone!

This is my first post here
Some days ago I recieved a PC from a colleague and he said that it suddently stopped working and he asked me to try to fix it.
The PC turns on, but there is no output display , although the display works fine. The fan spins very fast but then slows down. First I thought it was the RAM, but if it were the RAM the motherboard would have beeped, right? (And I tried turning it on with no RAM and still no beeps or lights) So I thought it was the PSU, so I tested it in another computer and it booted normally, so the PSU isn't the problem. Therefore it could only be the mobo or the CPU. I changed the CMOS battery, still nothing. I removed everyting from the case and just connected the CPU, the fan, the PSU and the RAM and still nothing. I tried to look out for a bent CPU pin, a burnt capacitor or something like that, and once more nothing.
He says that he can buy a new motherboard or CPU but he doesn't have the budget for both (and I wouldn't like to tell him to buy something that is already working).
Any suggestions of what could be the issue?

Here are the PC specs (also this is a prebuild PC):
Processor: Intel Core i3-4170 3.7 GHz Dual-Core Processor
RAM: Kingston 4 GB DDR3 (1x4GB)
ROM: SSD Crucial MX500 1TB (he bought recently)
Graphics: Graphics HD Intel® 4400, 2GB
Motherboard: ASUS H81M-P
Power Supply: Gold (300 W)

 

[rocktalkrock]

You say you changed the CMOS battery, but did you unplug the PC and clear the CMOS?

 

[SamHamm]

You say you changed the CMOS battery, but did you unplug the PC and clear the CMOS?

Yes I cleared the CMOS with the PC unplugged. And I used the jumpers to erase RTC RAM.

 

[DRagor]

And I tried turning it on with no RAM and still no beeps

Very good thinking here that you made that test. Unfortunately there is no way to make sure it's board (other then trying with another one which makes the test pointless). In cases like this I would call the numbers being 90% chance for bad mobo, 9% for CPU and 1% for both (yes, sadly such option can't be excluded).

 

[SamHamm]

Very good thinking here that you made that test. Unfortunately there is no way to make sure it's board (other then trying with another one which makes the test pointless). In cases like this I would call the numbers being 90% chance for bad mobo, 9% for CPU and 1% for both (yes, sadly such option can't be excluded).

Thanks for the reply! I told him to buy a new motherboard I will tell you if It works.

 

[SamHamm]

[Update]
So I connected everything to the new motherboard and, unfortunately, still nothing, I tried again removing the RAM and still no beeps.
Is it the CPU?

 

[DRagor]

[Update]
So I connected everything to the new motherboard and, unfortunately, still nothing, I tried again removing the RAM and still no beeps.
Is it the CPU?

Kinda stupid question to ask, but did you made sure beeper is connected to new motherboard?
At this point you excluded everything but CPU and RAM, and removing RAM does not change behavior, so it has to be CPU. At least as far as logic goes.

 

[rocktalkrock]

What is the name of the new motherboard? There could be a setting in the BOIS to make the built-in graphics as the default rather than an external GPU.