Question Everything went horrible on my PC ?

[cihs]

Hello,

I recently bought a new CPU and a case.
I put everything in the case and put the new CPU in to it's socket on the motherboard. Didn't go in. There was a bent pin.
I sent the new CPU for repair.
I put my old CPU back to the motherboard and turned PC on.
Fans spinned. GPU's fans didn't spin. No video output from MOBO or GPU.


I sent MOBO to service.
Today MOBO is back so I wanted to try the MOBO with the old CPU make sure everything works.
Now fans spin for a second and stop. GPU's fans don't move. No video output.
Same as before I sent MOBO to service except fans don't work this time.
Also hard disk activity light does not light this time.

Service report mentions they changed a burnt component on PCB.

I did paper clip test
Power supply worked. So did fans. And I also heard a sound like something booting.

I read somewhere they had a faulty sata cable and it caused PC to not boot.
So I removed all the cables that goes to hard disks except the one that has windows installed.
This time the fan attached to the motherboard worked. (I didn't attached the heatsink and fans that should be on CPU because once PC works I wanted to plug in my new CPU)
I could see screen is trying to get a signal.

So I plugged my GPU. GPU and fan that worked before didn't work this time.
I removed the GPU and tried again.
I received video output just enough to get into the bios and then it turned itself of.
I attached the heatsink and the fans. This time it didn't boot.

So last week it was working
I changed the case and now I can only attach a fan and a SSD and if it boots it closes itself in 10 seconds.

Any ideas?
I believe case shouldn't have any effect. Am I wrong?
New case has some fans attached to it.

My power supply is 850 wats ASUS PSU
My old CPU is 5600G
New one is 5700x3D
My graphisc card is 5700xt

Edit
Culpit was my RAM.
I tried with one stick and all of them and when I left only two of them suddenly it ran.

I plugged fans, SSDs and old GPU and everything worked.
Then I tried new CPU and GPU. It works fine now.

 

[punkncat]

This seems a pretty tough one to diagnose. Is the service center you have used close enough to take the whole system to?

This becomes a bit mroe difficult in that a couple of paid professionals can exceed the cost and value of a whole replacement system.

 

[cihs]

This seems a pretty tough one to diagnose. Is the service center you have used close enough to take the whole system to?

This becomes a bit mroe difficult in that a couple of paid professionals can exceed the cost and value of a whole replacement system.

Service that I used was AMD's and ASUS's own services for CPU and MOBO.

 

[CountMike]

Service that I used was AMD's and ASUS's own services for CPU and MOBO.

You should have sent them together, at least MB, CPU and RAM.

 

[cihs]

You should have sent them together, at least MB, CPU and RAM.

I actually wanted to do like that. Motherboard's service (ASUS) stated I should only bring the motherboard.
They also called and did really non friendly things too So next step is trying to reach to ASUS international

 

[cihs]

You should have sent them together, at least MB, CPU and RAM.

Do you know how can I turn it to solved status?