PsyntH HI there
Please try this and make sure you do it with all cables off
CLR CMOS
First, please unplug the power supply and HDMI cable.
Secondly, Please hit the “CLR CMOS” button/hole for about 10 seconds.
Please wait until 10 minutes later (THIS IS VERY IMPORTANT),
Then plug the power supply and HDMI cable back in, turn on the PC again,
once turn on the PC, you will need more than one minute to wait for the PC to enter the system.
See if it works. Please try few more times.