I’ve had a problem for the last week with my Blackberry (Curve) simply … not answering calls. I could see (by the in/out signal icons) that it was detecting something going on, and it would immediately give me a Missed Call message when it rolled to voice mail, but it would neither ring nor vibrate. (And, yes, I verified in the profile that it was not set to Do Not Disturb.) Which was rather embarrassing last week when I missed multiple calls from my boss because the phone was not ringing.
For my own future reference, I solved the problem by taking out the battery and SIM card for 10 seconds or so, then putting it all back together again. That forces the phone to go through a real boot-up sequence, which fixed whatever was causing it problems. Evidently this is not an uncommon problem, nor an uncommon solution.
And this is why I write this stuff down in my blog — so when it happens again, I can remember how to fix it.