I tried to install W10 on a second hard drive while my main HD was connected. Major problems now.
I could not reboot my main HD, and I could not boot my second drive. I wiped my second HD and tried to install W10 again, but no luck. Tried to repair my main HD with a USB drive with W10. No luck. Got an error.
Somehow I finally got my main HD to reboot. I'm afraid to reboot now. ;)
Not sure if I should unplug my second HD I tried to install W10 on while computer's running. Trying to go to previous build didn't help. Think I may have a system image on an external drive. If I boot from my USB and plug in an external drive with that backup image, will that re-write my main drive completely and take me back to that system image state? System Reserve and all?