Question No display on boot

[RoofRoof]

So my 1 year old prebuilt PC started overheating 3-4 months ago.It would freeze for a sec then I had to shut it down by holding the power button.No BSOD or anything.My CPU was around 50C without me doing anything.Fans were working.2-3 days ago it shutdown and so I re applied the thermal paste and put it in.I didnt get any signal to monitor.Fans were working also keyboard and mouse was lighting up.I tried booting without GPU,one stick of RAM also tried with another PSU but it didnt start.I took out the CPU again and realized I somehow some thermal paste on the pins and those pins got it to sockets.I cleaned them both with %99 alcohol.Also checked the pins for any bent ones but there wasnt any.After I put it in hoping it was that it didnt boot up again.

So I took it to the shop and guy said it was probably the CPU because it didnt heat up while booting and also he didnt check with another CPU since he didnt have any.It sounded stupid considering a dead mobo wouldnt also cause a not working CPU?Called the shop where I bought it they said it was the GPU but it didnt make sense either since it didnt boot without it too.I shipped both my MOBO and GPU to warranty today but wondered what could be the cause of it.There was no debug lights blinking on the MOBO even without GPU and it made me think that the reason it didnt boot because of the faulty MOBO.I'm hoping its not a dead CPU but I read that CPUs were much more harder to kill than the MOBO and the GPU.

I have a AMD Ryzen 5 2500X CPU
MSI B450M-A PRO MAX
MSI RX580

Everything is stock.Didnt overclock.

 

[rgd1101]

brand and model of the psu?

 

[RoofRoof]

brand and model of the psu?

FSP HyperK 500

 

[Ds_Tech]

Your processor don't have an igpu so a separate Gpu is needed to boot.
Try other board if your friend got any amd ryzen pc try in that.

 

[RoofRoof]

I sent it to the warranty. So just wondered what could be the cause. Does not having debug lights even without Gpu sign of anything