I have a motorola starTAC cell phone 7700 series. I have 100 names and
phone numbers in the memory. for some reason, starting today, when I
go to my phones phone book it says "empty" and when I try to recall a
phone number by name it says" no a's ". It tells me this for every
first letter of any name that I try to find the number for. When I
recall a number by location it gives me the phone number but not the
name it was listed for. Now I have 100 phone numbers in my phone
memory but I dont know which number belongs to which name. my
question: how do I reset the phones phone book so that I can pull up
the phone numbers that are already in the phones memory by the first
letter of each name again like I could before? This may seem like a
minor problem,but without knowing which number belongs to which person
I cant call my mother as I used to be able to pull up her number by
entering the letter "m" and by searching the numbers in the phone I
dont know which number is hers.
thanks for your time. My mother and I thank you.

Have you tried removing and re-seating the SIM card in the phone? 
(It's just a thought.)