I'm bumping this thread because this just happened to a friend of mine. It's a bit more complex then that though.
He was running Windows 7 and a window popped up not matching the theme of windows 7 saying "Windows 10 is now ready to install. Would you like to install now or be notified at a later time?" He selected to be notified at 3PM. Right behind that was a "Your computer has important updates. Restart to install now" window. He restarts the computer and Windows 10 immediately installed instead of waiting.
Now his computer starts up with the Windows 10 theme, but clicking "I'm not xyz" the "Show password" icon, or the "Next" button does nothing. A second click turns the cursor into a loading wheel, and eventually (or after a third click) you get the "white tinted not responding" filter over the whole screen, then the computer goes black causing you to manually turn it off.
He's on the line with Microsoft support so hopefully he can get this fixed. I'm suspecting he may need to format the HDD and re-install 7 though.
**UPDATE**
This is makes no (curse words) sense... but unplugging the router fixed it... I don't know how but after several failed restarts, terminating the internet connection in his house fixed it.
Microsoft, please fix.
**UPDATE 2**
Typing these as they happen because, woo-hoo, more issues.
Task manager doesn't refresh at all and the WiFi adapter doesn't work. Trying to update the wifi's drivers via USB just ends up freezing too. This looks an awful lot like the wifi drivers issues Yosemite had on Mac.
Friend is restarting computer... stuck in restart cycle at this time.
"Your PC has confronted an error and needs to restart. Collecting data..."
Uhuh.. so, it's restarting during a restart because it encountered a problem restarting.
Computer restarted. Didn't bother updating anything. Left it run idle, and then tried opening Steam. Desktop tinted white and taskbar turned solid white. "Windows 10 has stopped responding" showed up twice after clicking "close program." Final verdict of today is he's gonna have the friend who helped him build it come by later and either try and fix it himself or just format it and re-install 7.
I'd be more forgiving if this was just a failed update on his computer, but he clicked "Remind me later" and was prompted to immediately restart anyways and windows 10 forced installed on his computer. I found a similar article here:
MS forced install to Windows 8.1 after I click on Remind me later. - Microsoft Community
I know I'm gonna update to Windows 10 eventually, but this just raises red flags all over and leaves me very cautious of it.