I tried to help Nokia/Microsoft out last week. My daughter switched from Android to Windows Phone 8, going from a (well behaved and loyal) HTC Desire S to a Nokia Lumia 620.
After a day of faffing setting the thing up (like not really understanding how the whole Parental Control thing worked - because the MS account I thought I'd tied to the phone thought I was 12 and not 42 for historical reasons - I was confused as to why I needed to ask my parent to give me permission to give my daughter permission to download Windows Apps... However, I digress...) my daughter got five days use out of the 620 before it bricked itself. (What it actually did was freeze completely, not even responding to the physical on/off button, after 20 minutes of cursing at frozen phone I gave up and removed the battery. On replacing the battery, nothing happened. Plugging it into the charger, give me a red bar battery indicator and nothing else. A day of charging and still nothing. Nokia (via Twitter) suggested their Software Recovery Tool, but the SRT and indeed Windows 7 or 8 refused to acknowledge the phone was plugged in via USB other than to tell me that the device had been disconnected (without it seemingly "connecting" to start with).
So, the phone's going back to Amazon who offered a no quibble refund. Unfortunately my daughter still wants a WP8 phone and although I'm hoping the set up will be easier I'm loathe to try another Nokia...
(Any suggestions for an unlocked Sim-Free, sub-£200 WP8 based on personal experience, gratefully accepted!)