I keep getting kicked by PunkBuster for "Blocked O/S Privileges"?
Please temporarily disable other security type programs you have running such as anti-virus, process guard, SDProtector, etc. to find out which of them is blocking PB's access to resources on your computer. You either need to run PB without the blocking program(s) or play on non-PB servers. Also make sure you run the game under an Administrator or equivalent account under Windows. If you do have access an admin account, you can right click on the application you want to run and select "Run As". This will allow you to give admin access to that program and should allow you to play with a limited user.