I have huge problem with my Lumia 820. Few minutes ago some information appeared on a screen. I tapped it and something has been installed. From this time on a screen a can see emot ":-(" only. I can switch off my lumia only by putting out battery... But it doesn't fix the problem. Emoticon ":-(" is still there and Windows is not starting. I tried restart phone by pressing buttons combination but it's not working.
How can I fix it? Please, help me!
Windows 8 generates a 'sad face' screen when a fatal error occurs in kernel mode. Windows Phone 8 is based on the Windows 8 kernel, so I assume that the sad face means the same on the phone, although it's not showing any details of what went wrong.
Most likely the update wasn't written to the flash memory correctly, and therefore the new code is hitting an error. Generally I'd think it was too big a coincidence that a hardware failure occurred at the same time as installing an update, assuming that it was the update to the OS rather than updating an app.
In either case, it's very unlikely that allowing the battery to go flat will do anything. In fact, since the 820 has a removable battery I'd just remove the battery, leave it for 10 minutes or so, then reinstall the battery. You could see whether removing the SIM and MicroSD (if you have one) makes any difference, but again I suspect you will need Nokia to repair it.