Anyone know if there is a way to "LOCK" settings on an iPhone?

[EarlG]

3. This doesn't really answer your question about locking the settings, but

does your phone have a little physical switch on the outside which turns the ringer on and off? My iPhone has one, and I usually keep it in the off position otherwise the phone makes annoying beeping and bonging sounds all day. However this does mean that when someone calls, the phone vibrates instead of rings, so sometimes I will miss calls (not that it matters because 99% of the people who call me are spammers).

Anyway just a thought -- sometimes I do want the phone to ring but it doesn't because I forget that I have the little switch set to off. Just wondering if that might be a factor, it could explain why the phone sometimes rings and sometimes doesn't.