Computer is a modified HP Pavilion TP01-0157c. Erica motherboard; Ryzen 5 3400G APU. 12GB RAM, 256GB NVMe drive, 1 TB SATA HDD. Modification consists of upgrade to HP OEM 400W PSU (L04618-800) and the addition of a Visiontek Radeon RX 560 4GB. The GPU is bus-powered and the PSU provides more than the rated power requirement (yes, I checked). Outputs via mini-Displayport. Ryzen Master had been on the machine prior to the upgrade but is not doing anything; standard configuration.
Machine had worked fine until the 21.5.2 driver update last night. Suddenly it can't recognize my monitor, sees it as a 640x480 generic PnP. I used Windows control panel Apps/Features to remove the Radeon software in an attempt to redownload and reinstall last known good version. Once I did that, the following happened:
[ ] Web browsers will not "let go" of downloaded files. I can't launch applications like the cleanup utility from Downloads because the browser won't complete the handoff of the completely-downloaded file to the file manager. Browser hangs. When I try to close the browser it deletes the file.
[ ] I cannot launch the command line, either vanilla or Admin mode, from the Windows menu, the taskbar, or via Windows search. So, no sfc or any utilities like that.
[ ] I cannot open device manager.
[ ] I cannot boot into safe mode; any of them. F4, F5, etc. from cold start don't do anything.
[ ] I cannot shut off or restart the machine from the Windows button.
[ ] I cannot get into any of the Recovery options, launch Reset, or any of those other options from Control Panel or from shift-Restart.
Obviously this is frustrating. I'm looking for advice on how to get my machine, which is 3 weeks old and worked perfectly prior to this, back into the same condition it was in before that disastrous driver update.
Ended up solving this myself. Booting with F11, F4 or F5 never ended up working. Did another power-button long-press to turn the machine off; when I rebooted the machine I was able to get Shift+Restart working from the LOGIN screen/splash screen. I'd never done that before but shockingly enough it worked. Got into recovery tools and rolled back to a system restore point from before the driver update.
Now I just need to remember to never update Radeon drivers without 2 weeks of forum feedback reading first.