I have a Lenovo All-in-one PC with the UHD Graphics 620.
Worked fine for the first year, but since then booting is a problem, with the graphics card apparently being the issue.
When booting, the PC will beep 5 times (2 low, 3 highs), with "Input signal is not detected" displayed before everything goes black. Since the PC is an all-in-one, I have no monitor to connect so this is especially strange. If I try a few times, it will eventually boot properly. But it's always a struggle and concern that it won't reboot at all.
The warranty having expired, Levovo has been of no assistance. I have found no information to explain the beeps. I have the latest UHD 620 driver installed (220.127.116.1116).