empty globle address list in outlook (it is the first requst)

befor one week i have problem in recive email on my exchange server couse one of the it stuff change the web mail account without changing the pop3mail acout then i fix it and restart the domain controller and exchange server after that when the user go to the globle address list in outlook 2000 it dosn’t appear but when he press find in the address book and but aletter it show hem every adrress start with that letter
so can u help me pleas its avery critical problem for me