I have a N900 that I got a few years ago and have barely used. I went to use it recently and noticed something familiar - it won't ring. It appears to be setup to ring but when it is dialed is it won't ring and in the dialog that pops up one box displays a RED SLASH over a speaker icon, apparently showing ringing is turned off.

This is under the General profile which is set to Vibrate (it does vibrate) and a Ringing Tone of Nokia Tune. For the Ringing tone the tab is on the right, leaving the rest of the bar blue. If I move the tab to the middle, leaving half the bar blue, it also does not ring and still shows a red slash through the speaker.

Reflash the entire thing then install cssu
give it a fresh start as you are inbound be getting more nasty problems on a unupdated device