Initial Log In Screen on Window 10 Blinking with Facial Recognition Logo. (I cannot Login)

I had the same problem. No keys working. Nothing. Just the screen flickering. 

What I did was kept on pressing Ctrl+Alt+Del for as long as the manual log in screen appears. I pressed it for 30-40 seconds. If that doesn't work then keep hammering the same key combination until the manual login appears.

Uninstall the Fast Access facial recognition software.

Dell XPS 15| i7| 8GB

I had the same problem. No keys working. Nothing. Just the screen flickering. 

What I did was kept on pressing Ctrl+Alt+Del for as long as the manual log in screen appears. I pressed it for 30-40 seconds. If that doesn't work then keep hammering the same key combination until the manual login appears.

Uninstall the Fast Access facial recognition software.

Dell XPS 15 | i7 | 8GB

I had the same problem. No keys working. Nothing. Just the screen flickering. 

What I did was kept on pressing Ctrl+Alt+Del for as long as the manual log in screen appears. I pressed it for 30-40 seconds, it might take longer too. Just don't give up. If that doesn't work then keep hammering the same key combination until the manual login appears.

Uninstall the Fast Access facial recognition software.

Dell XPS 15| i7| 8GB

Right, so the first trick is to get into safe mode, which is hard to do in 10 if you can't log into your computer. For some inexplicable reason Microsoft decided only to let you reboot into safe mode after you log into your computer normally...which kind of defeats the purpose of safe mode.

There are two ways. First, you can use the Windows 10 clean install tool offered by Microsoft, to create a bootable media. This is probably the easiest way. You will be able to get into repair functions (including rebooting into safe mode) that way. You might have to poke around a bit, but the option is there.

http://www.microsoft.com/en-us/software-download/windows10

Alternately you can trick your system into booting using legacy mode, which will allow you to hit F12 right at boot to get into setup. I believe if you interrupt the boot cycle (by turning off the computer partway through--hold down the power button till it shuts down) it will go into repair mode eventually, allowing you to get in here (I think that's how I did it). But the repair ISO is probably a safer bet.

Once you're into Safe Mode you'll be able to get in. The trick now is uninstalling Fast Access. Windows doesn't activate its uninstaller in Safe Mode. You can, however, fix this. Here's how:

www.raymond.cc/.../ ;

As an addendum to the above, your Start menu won't function in safe mode, either. If you right click on the Start button, however, you'll bring up a popup menu with all the options you need. 

Once you have the uninstaller running again, simply go into Control Panel and uninstall Fast Access. Reboot normally. Problem solved!!!

Here is what worked for me:

Boot in the safe mode, as suggested by annerisa. 

"

You can enter in safe mode ;

- Turn on the Laptop

- Immediately   +   , keys, at the same times, or also you can keep pressing and hit quickly many times, until appears "please wait"

- Then select:

     Advanced repair options -> Trobleshoot -> Advanced option -> Startup setting -> Restart ->F4 or F5

"

After that, go to Settings and subsequently, user accounts. If there is only one account, remove the password to it. If there are multiple ones, remove password from it, and make it the default account. 

Along with this, I also renamed the FAService and FAstartup files and added ".old" to the names. Not sure which worked, or if a combination worked, but this helped me log on. 

I experienced something similar to this. After my first reboot post Windows 10 install, the login screen just flashed, as if there was a loose connection in my VGA cable, or TV interference. The effect being I couldn't login or use my machine. After much research trawling the 'net, it seems that 'FastAccess', a product from Sensible Vision, that came with my 3 month old Dell laptop, isn't compatible with Windows 10. Or at least the version I had isn't compatible. Sorry, I don't know which version it was. To disable it, I had a bit of a nightmare getting into Safe Mode and could only get to a command prompt. As I wasn't able to uninstall it from the command prompt, to prevent it starting at boot I renamed the FastAccess folder within c:\Program Files (x86), giving it the extension '.old'. Actually,  I can't remember if that was in a 'SensibleVision' folder. Either way, renaming either of these will have the same effect. I rebooted and voila!, a normal login screen. As I wasn't using FastAccess and didn't want it, I uninstalled it (after removing the '.old' from the folder to allow the uninstaller to do a clean job). All now seems to work fine (I only did this a couple of days ago). Hope this helps.