It's been a great phone for nine years, but a few days ago the ringer quit working. The phone is set to ring and vibrate, it still vibrates but no ring.

I tried changing the ringtone, didn't work, checked all the settings I could, they are as they should be.

May or may not be related, I installed a new battery last week, and I believe the ringer was working before the change. I don't get a lot of incoming calls. Since the change, a strange icon appears on the screen when the phone is being recharged. Neither I nor my girlfriend can make it out, but it appears to be a square with a checkmark above it. Switching back to the old battery didn't help. It's the third battery I've installed, all from the same supplier, same batch.

We're in a poor reception area, and this is the only phone we've had that works in the home so I'd like to repair it.

Any thoughts?