I finally got mine working. I had two issues. ICloud isn't compatible and the installation removed my Norton Security Suite. In order to remove ICloud, you can't do it in Safe Mode, I had to boot up in Safe Mode by holding down shift while selecting restart. In safe mode, right click on the Windows icon in the lower left corner. Click on "Run" and type "MSConfig" then click "OK". On the general tab click on diagnostic startup, apply and then ok. Restart the computer. It should start and not be blinking at this point. Right click on the Windows icon again and at the top of the list click on Programs and Features, scroll down to ICloud and remove it.
In Norton's case, I had to download an app from Symantec called "ScreenFix". I couldn't get internet access no matter what I did so I went to my wife's laptop and downloaded it. I copied the app from her download directory onto a thumbdrive and then ran it "As Administrator". It didn't appear to do anything but when I rebooted after going back into MSConfig and setting it for Normal Startup, it didn't flash anymore and worked normally. Once I did this I went back to Comcast's site since I have them as a service provider and can get Norton free and reinstalled Norton Security Suite.
I know it's a lot but this is what got me going. What a pain in the ****! Microsoft should have had this stuff figured out before they made Windows 10 available. I hope this is helpful to at least some of you.