New build not working

I built a new computer using the following components:
Quiet PC Nofan A470 Silent Tower (my old PC case)
ASUS Prime Z690M-PLUS D4
Intel Core i7 12700 Alder Lake-S CPU
Noctua NH-P1 Passive CPU Cooler
CORSAIR CMK32GX4M2E3200C16 VENGEANCE LPX 32GB ram
Samsung 980 PRO 1 TB PCIe 4.0 M.2 drive
Nofan P-500A Silent 500W Fanless Power Supply Unit
ST-OB2 Slot-Load Blu-ray Reader

When I switched the PC on for the first time, the power led flashes (it should be on). The monitor says: no signal detected. I connected the monitor via the mobo HDMI connector to my monitor which worked with my previous PC and works with my laptop. I have no idea what the fault is or what to do about it.

I don't hear any beeps when I switch the PC on. I stuck the Windows 10 installation disc into the Blueray reader drive and I can hear it spinning and reading the disc.

Can you help?
 
I resat the RAM and the problem is resolved. Go figure...I could have sworn it was inserted properly in the first place....
 
I built a new computer using the following components:
Quiet PC Nofan A470 Silent Tower (my old PC case)
ASUS Prime Z690M-PLUS D4
Intel Core i7 12700 Alder Lake-S CPU
Noctua NH-P1 Passive CPU Cooler
CORSAIR CMK32GX4M2E3200C16 VENGEANCE LPX 32GB ram
Samsung 980 PRO 1 TB PCIe 4.0 M.2 drive
Nofan P-500A Silent 500W Fanless Power Supply Unit
ST-OB2 Slot-Load Blu-ray Reader

When I switched the PC on for the first time, the power led flashes (it should be on). The monitor says: no signal detected. I connected the monitor via the mobo HDMI connector to my monitor which worked with my previous PC and works with my laptop. I have no idea what the fault is or what to do about it.

I don't hear any beeps when I switch the PC on. I stuck the Windows 10 installation disc into the Blueray reader drive and I can hear it spinning and reading the disc.

Can you help?
I have the same MB with a i5-12400 and tested my VRMs by running CineBench23 all cores for an hour. The highest temp was 40C on HWiNFO64 v7.16. Could you run the same test and see how hot your VRMs get?