windows phone 8 failed update, sad face appears. How to fix it?

Try this :D

Turn off the phone, Once the phone is off, Hold the Volume down key then plug the charger (charger should be connected to the power source ",) Once you see the excalmation ( ! ), remove your finger from the button.

Then press the following keys in, Volume Up, Volume Down, Power Key and Volume down. The phone will turn on automatically, this may take several minutes and it will show two gears that are spinning just wait for it to finish.

One more thing all the files on the phone will be deleted but if you have a microsoft account on the phone, check people.live.com to check the contact lists that you have and skydrive for the pictures, that's if you have a microsoft account on the phone.

cheers!

You sir, deserve a medal for this. First time ever I experienced the frownie face after failed soft reset. Love the combination of keys that have to be pushed to activate the hard-hard reset

What if that doesn't work and it continues to do the same thing

i tried it on my Microsoft lumia 550 and it dont work

I also had the gears and sad face, which never stopped and couldn't get my phone to restart.  I tried all the recommendations to here hitting the up volume, down volume, power, etc to try to get the exclamation or some other response, but nothing worked.

I finally had to download the recovery tool on my laptop.  When prompted, I hooked up my phone (Nokia Lumia 920) to my laptop.  Unfortunately I lost all my photos, videos and contacts, but at least my phone is working again.

Here's the link I used:  https://www.microsoft.com/en-gb/mobile/support/product/lumia920/faq/?action=singleTopic&topic=FA144103

Since then, I have learned that you should sync your phone to icloud, so all your info is saved and retrievable, should this ever happen again.

Hope this helps.