I have lost my address book contacts when synchronizing my pc with my phone
When synchronizing your mobile phone with a computer all your contacts are lost.
Try this solution :
Do a search for AddressBook.data.previous
If you find this file another file called AddressBook.data, should be in the same folder , this will be the empty one.
Drag the file AddressBook.data to the desktop and rename the AddressBook.data.previous to addressBook.data
Now reopen AddressBook