Why does the computer not work after assembly?

Question

Computers

Hello.
Thanks in advance to everyone for the replies and recommendations. Today I built my first computer on AMD.
amd am4 assembly
1) MSI B550-A PRO motherboard
2) AMD Ryzen 7 PRO 2700 OEM processor
3) Kingston HyperX FURY Black RAM
4) PCCooler GI-X5B [CLPCC_X5] CPU cooler
5) HIPER HPA-550 power supply
6 ) I didn’t buy a video card, I connected an old working one. (I can throw off the screen if necessary)
After the assembly I tried to start it but it does not work ..

1) When you turn on the black screen.
2) I tried with 1 chip of memory operas did not work.
3) Somehow I tried it strangely without RAM and then, as usual, it worked, I thought it would swear at startup ... but no.
4) What do I need to do?
5) No one I know has a percent ryzen, what should I do?

Answer 1

Your motherboard only supports 3-series and newer processors
https://www.msi.com/Motherboard/support/B550-A-PRO...
logically it won't start with Ryzen 2700

Answer 2

Try pci post card to find out exactly where the hang is
. But in general, 99% is RAM. Not listed as compatible HyperX RAM

Answer 3

Cookies. Hand over the percent back, 14 days if it has not passed. This is not a technically complex product, they must be returned, and if you contact and ask for a replacement, and not a refund, then they will definitely change it, if this is not Uncle Vasya's store around the corner.