I have rec'd basically the same instruction from my Level 2 Microsoft tech, but he wants me to call back in a month. Verrrrrry long story short, three days ago level 2 installed 8.1 Pro for me, was working fine and he told me that I would be fine with all future updates. Sadly I listened to him and not to all of you as the next day the 18 critical updates showed up, including the kb one ending in 939 you've all been saying to avoid. Well I thought how will I know if it's a problem in Pro also if I don't do it? So I did them all and back to black screen.
Again Level 1 nonsense yesterday but I didn't let it go on for too long before requesting to escalate to level 2, who called today. Three and half hours later i'm back at least to a working 8.1 Pro. He updated the BIOS for 8.1 which he dowloaded from HP support site. (He had disabled display driver I think). Then downloaded all updates, and again black screen. Restored and went through the process again, this time updating BIOS then only the 17 updates not the 939. Restarted then installed 939, again black screen after enabling driver. I think he had forgotten to set restore point so back again to restore and had to do the BIOS again, then the 17 updates and hid 939. Back to working machine.
So he said not to do any updates for a month, then to call back and request level 2 right away using my case #, and they would let me know whether it was safe to do any updating. Turned auto updating off.
Realized I lost my "sleep" option in Power Options - has this happened to anyone else? A search turned up a possible video driver issue.. definitely not updating anything now. Was able to add hibernate through control panel power options, unless anyone out there knows how to fix short of updating anything that's what I'll use for now. Maybe will return with future safe update.
Also can I ask all of you that are the real techies out there.. are you comfortable with this machine overall? I'm so drained from all this I hardly know how I feel about it, and HP was no help.. seriously considering plopping down an insane amount of $$ at the Apple store for a Macbook Pro.
Thanks for all your help and good luck to all.