Question PC working but no display on screen

Nov 17, 2021
Hello guys, so where do I start. I have an old pc that haven’t used for approximately two years, yes two years. So I have finally found a permanent place to live and got the pc mailed to me. I turned on the pc everything seemed to work in there everything was lighting up the way I remember it. Although there was no display on the screen. (Computer specs: MSI R9 390X (GPU) MSI 970 Gaming (motherboard) AMD 8370 (CPU) and a cooler master 750watt power supply.
What have I tried:
Cleaned the computer
Checking if the monitor or the hdmi cable is faulty
Checking and rearranging the Rams into the slots
Taking out the CPU and replacing thermal paste
Checking the connections from the PS to the motherboard
Checking to see the CSMOS battery
Check the graphics card

I still don’t know what it is, if anyone knows or has wxperienced something similar and can help I would be grateful to you guys

thank you