After declining the WDOs 10 update at least 75 times over the past few months, I turned on my computer yesterday and found the “upgrade” “in progress”. It decided it was going to upgrade me whether I liked it or not. This was yesterday, if that means anything to your situation. Well...if you know PCs even as sketchily as I do, the one way to completely obliterate the functionality of same is to shut off an in-progress OS change. So I let it go. Installed properly, but my second monitor would not work, and device manager did not see it (my video card) and could not see it, therefore, there was no way to correct the problem.
I do not know for certain if this is your problem, but I would bet 90% that it is. The very simple fact of the matter is that installing WDOs 10 will obsolete some or all of your existing drivers. This, that, and the other thing will thus simply stop working, and if you wish to retain the use of your existing hardware, you have to get drivers. Except....that since 95+% of drivers these days are plug-n-play, if after the OS install there is no driver it’s a fair conclusion that a driver for whatever you have does not exist. Now you either go buy a new whatever or go back to WDOs 7/8.
I futzed around w/MSFT help for only about an hour. I called the manufacturer of my video card and found out in 30 seconds that there was no WDOs 10 driver available. Nothing to think about. If there is no driver available, the chances are 99.99% that you will never be able to make it work. End of story.
The same happened to my husbands computer here at home. When he got home from work his computer was almost done up dating to Window 10.
He was furious!!!
When it completed the up date he said he wanted his older Windows....It stated it would take some time to get the old information back. He said he wanted his other Windows. It took about 15 minutes but it did return back...
I had 10 installed yesterday against my wishes too, I left my machine to get coffee and came back to find it installing 10.