[knives of ice]

really stumped with this problem that just started out of the blue, i haven't loaded or used any new programs in weeks. thanksgiving day i turned my phone on vibrate which i rarely use. now after turning the ringer back on the phone will not ring or vibrate when i receive calls. the phone lights up but thats it. the volume is turned up the whole way. any ideas on what to try? i know i could hard reset but i really don't want to do that unless its absolutely necessary.