Pnkbstrb.exe is a PunkBuster Software process. It is installed by online PC games such as Call of Duty 2, Battlefield 2 and America’s Army Version 2. It launches automatically at computer startup and works as an anti-cheat program for these online multiplayer games. PunkBuster can be removed from your computer if you no longer need these games. This simple process can be accomplished using a supplied uninstaller that removes the drivers from your computer system.
Navigate to the PunkBuster FAQ page (see Resources). Click the "Here" link under "What is all this about new PunkBuster services?"
Click "Run" to download the uninstall link. When the link has downloaded it, the uninstall wizard will automatically launch.
Click the "Uninstall/Remove PunkBuster Service" radio button and click "Next" to uninstall and remove it from your computer.