New
#41
Well, the experiment seems to have worked, at least with the KB5057142 update is concerned. It downloaded normally, and the computer rebooted properly into normal Windows, without the black screen. Of course, that doesn't mean everything's good - still lots of errors in the event viewer log, "ATI EEU PnP start/stop failed 16396", DistributedCOM, and Bonjour Service being the most common.
I've tried every single version of Memtest86 5.01, and can't find one that will work. One of them turns out to be a VLC video file (VLC says it's a video, but not a recognized codec), the USB version doesn't recognize any of my USB drives, I don't have a floppy drive, and the bootable ISO versions just give me a system error message that "Virtual hard disc files can't be mounted from image files, or from removable media that isn't formatted with the NTFS file system", and won't go any further.
I did manage to fool it into loading onto a USB, but all that's there is a brief text file, explaining Memtest86's purpose & where to find on the net. There were no actionable files.