Question PC won't boot after installing m.2 SSD

[abelincoln]

After many problems involving different motherboards and finally getting my PC working again, I installed an NVMe drive (Samsung 980) to make things faster. However after doing so my PC won't boot at all. When I plug the power cable, all that happens is the Power led on the case starts blinking. I removed the NVMe drive but still all there is is that blinking led and nothing else. I could use your help...

Edit: here's a video of the flashing led

https://imgur.com/xnFuEmS

View: https://imgur.com/xnFuEmS


My build as it stands now:
- MSI B760 Gaming Plus WIFI
- 2x16GB DDR5 RAM
- 500 GB SSD
- 2x 1TB HDD
- GeForce 1060 6GB
- Corsair TX650W PSU

 

[Lutfij]

Corsair TX650W PSU
How old is this unit?

You forgot to add the make and model of the case and that Apacer card reader at the front with a flashing power LED doesn't bode well for a system.

 

[abelincoln]

Corsair TX650W PSU
How old is this unit?

You forgot to add the make and model of the case and that Apacer card reader at the front with a flashing power LED doesn't bode well for a system.

It must be about 10 years old, and so is the case. The case is by Cooler Master, but I don't remember the model.

Do you think it's the PSU? It was working fine 5 minutes before I switched off the PC, opened it up and installed the NVMe SSD...

 

[abelincoln]

Corsair TX650W PSU
How old is this unit?

You forgot to add the make and model of the case and that Apacer card reader at the front with a flashing power LED doesn't bode well for a system.

Are you implying it could be the card reader?