Unable to sync i phone 4s with i tunes

For the last two months I have been unable to sync/backup my i phone 4s with my computer/i tunes at work. I have tried uninstalling i tunes, deleting old libraries but as soon as i hook up, it gets to stage 2 and sticks.

At first I was getting an error message saying the computer was unable to back up, now nothing?

I am using a PC with windows 7 home edition, I have tried everything.

I can sync and back up to my PC at home running the same system?

Both computers are authorised?

Help!

You mean iPhone 4, since the 4S was just released a couple of days ago..

Anyway..has sync'ing to your work PC ever worked? If it did, when did it exactly stop and with what error?

Sorry, it is indeed an i phone 4!

I get this error massage when I start the computer-

AppleSyncNotifier.exe Entry point not found

The procedure entry point
Sqlite3_wal_checkpoint could not be located in the dynamic link library SQLite3.dll


Dont know if it was an apple upgrade or a microsoft upgrade that caused this?

Thanks, Alister