After the most recent Battlefield 3 PC patch, some players have reported being unable to play Battlefield 3 online at all as they receive the PunkBuster error below:
To resolve this issue, follow the steps below:
Download and install the PBSVC program from http://www.evenbalance.com/downloads/pbsvc/pbsvc.exe
Open the program and Uninstall PunkBuster This will clear any older versions of PunkBuster that may be experiencing an issue
After uninstalling the program, download and run PBSetup from http://evenbalance.com/index.php?page=pbsetup.php
Once downloaded, open PBSetup and select Add a Game and add Battlefield 3 from the available list.
After adding Battlefield 3, click Check for Updates until you receive a message stating No New Updates Needed. This may take several updates depending on the game and version of PunkBuster.