Nokia Lumia 920 battery draining in 4-5 hours with no usage, after an update

[Londoner2014]

I have downloaded updates on my Nokia Lumia 920 about 3 days ago. Everything was fine for a day, then yesterday the phone started overheating and the battery drained in just over 4 hours without me even touching it. I stopped all background apps, recharged it to 100% and the battery is still draining very fast. I tried to turn the phone off, but it restarted itself. After turning if off a few times, it stayed off. I also noticed, that since this problem with the battery, the Calendar is not working any more (which worked right after the update), there are no appointments in the calendar at all, but it still gives me notifications of the next appointment on the main screen.
Althought the battery is still draining like crazy, its no longer overheating.
Tried to do soft reset, the phone is not having it.

Anyone has any good ideas what to do? I cant use the phone at all, as soon as I start using it, the battery drains even faster.

 

[aikidaves]

Have you let the battery drain all the way out until the phone shuts itself off before recharging? If you can't soft reset, that's the next level fix. If that doesn't work, the next step is hard reset.

 

[Londoner2014]

I managed to turn it off in the end (about 20 tries before it stopped restarting). I kept it on the charger to fully charge it, then turned it back on. Still the same, draining battery in a few hours.

Then I remembered that my friend's boys were playing with a game called "Frozen" on it and told me that when they changed the screen to show the picture of the game bigger, the screen froze, even after they closed the game. So I deleted that game and a few others. Then the screen started shaking and flashing and the phone wondered around the menu on it's own, it looked like a contact problem.

I turned the phone off a few times (was still restarting itself) then it finally stayed off. I left it off and on the charger for a day, then turned it back on. Since then, everything is fine, it's charging faster and discharging slower and slower (currently around 1.7-1.5 % per hour when I don't use it, which is a big difference from the 25-27% I had before.) Everything is working perfectly and I haven't experienced any problems for weeks now

I am not sure how I "cured it", as it was still acting up after I deleted most of the games, including Frozen. I am sure I will not download too many updates at the same time, or get any games on it any more.