Cant start the car

What is your question?

I just purchased this vehicle and the key fab is not communicating with the car! I checked the fab replaced the battery in the fab and had it checked and ok on that end, The battery was dead and I replaced it but wont detect the fab, I pressed the ACC button on the start button on the dash it said to wait 10 minutes I thought this would link up again with the fab but did not work, I cant do anything with the fab, door locks, trunk or alarm button nothing works! wont start!

What makes this problem better or worse?

Nothing

How long has your 2006 Cadillac STS had this problem?

just purchased