Windows phone 8.1 upgrade gone bad

My Wife has a Nokia Lumia 620, at the beginning of the week she received a notification her phone that the 8.1 upgrade was available. Since upgrading she's had endless problems

- Phone randomly turns itself off despite having charge (have to take battery out in order to be able to turn back on again)
- Won't load apps such as Kindle
- Photos appear blurry
- Bad mobile signal
- Keep having to 'forget' the wifi network and re create it

And probably a few other things. Googling seems to turn up a few other results of similar stories. It apparently isn't possible to roll back.

So given Microsoft/Nokia (whoever) has pretty much bricked the phone for her, does she have any course of action she can take?

Use the new backup option in settings, then perform a hard reset. It'll all be fine after that.

First stop would be to download the 'Nokia Software Recovery Tool' and try re-installing the phone with the latest Factory image.

http://www.nokia.com/us-en/support/faq/?action=singleTopic&topic=FA142987

Be warned you will loose all data on the phone, including, if I recall, a wipe of the SD card! so Back up anything you don't want deleted!!!

After the Factory reset, and you've logged back in on the account, the phone should start re-installing all your apps. but you will need to set them up/log-in to them again!

if this doesn't sort the above problems, you'll need to contact Microsoft of Nokia (or both) for further help!

I had to do this with my wife's 620 when the 8.1 Developers update bricked her phone, it was stuck on the 'Cogs of Death'... once I re-set everything (took me 3 goes as it didn't recognise the phone due to the Boot-Loop) the official 8.1 update came through and all was well!

Ok thanks, will give that a go!

It's a pain, but resetting it should resolve all issues. Maybe even start afresh rather than restoring a backup.