my apple tv 3rd gen is blinking a white light all the time and won't show any video on my tv what do I do

Welcome to the Apple Community.

Try the following steps, check whether things are working after each step where appropriate, before trying the next.

1. Restart the Apple TV (Settings > General > Restart).
2. Restart the Apple TV by removing ALL the cables for 30 seconds.
3. Restart your router. (Also try removing it’s power cord for at least 30 seconds)
4. Reset the Apple TV (Settings > General > Reset > Reset all settings)
5. Restore the Apple TV (Settings > General > Reset > Restore)

Did you have the blinking happen right after updating? Or did this happen at a later time?

I tried all these remedies. The problem is I cant get to the settings. ATV sends only a graphic showing HDMI cable.

HELP!!!

Have you tried switching HDMI cables?

That graphic is of a micro usb cable, it's telling you to restore via iTunes

Apple TV (2nd and 3rd generation): Restoring your Apple TV - Apple Support