Windows blacks out after installation

[mongini12]

Hey guys
i have a weird issue with a build im doing for my father in law.

System Specs are...
Gigabyte B450M S2H (latest bios is freshly flashed)
APU Ryzen 3400G
2x4 GB DDR4 2400
400W Enermax PSU
500GB Crucial MX500
 

The installation process runs as usual... giving it the Key, reboot, say no to all the data collection bs... you know the drill... but after that i just get no image whatsoever... if i reset the machine, i get the BIOS and boot screen, after that, my display (connected to the MB HDMI) just goes into standby, cause apparently PC doesnt send anything.
RAM is checked in my machine, working fine... resettet the bios to default as well, no change

does any1 of you have a clue what else i could try?

**EDIT** The PC is visible in the network, so it is booted

[mongini12]

okay some updates on this...
i plugged a secondary display on the DVI - works for around 3-4 seconds and then turns into fine noise.

i used these time windows to install teamviewer quickly. remote controlling it, everything works fine. then i installed the latest AMD Adrenalin version. When the installer uninstalled what windows had installed by itself the HDMI connected display worked fine, the DVI went in standby. then i installed the latest AMD driver for the APU aaaaaaand it was gone again... so - i get a working image (tho not 100% reliable) if no display driver is installed... do i have a faulty APU ?