First- if you have reconfigured your in game key settings I suggest backing up your Controls.con (found in My Documents/Battlefield 2142)
1. Uninstall Battlefield through Control Panel/Add or Remove Programs
2. Check your firewall program (if you have one) and remove any access settings
3. Reboot then install Battlefield 2142 using your Disk or Via EA Link
4. Install Full Patch 1.25 downloaded via EA Link or battlefield website
5. Install Northern Strike
6. Install Full Patch 1.25 again
7. Start the game in single player mode to check if the installation installed OK
8. Your Firewall may stop you! Give full access to Battlefield and punkbuster EXE’s
9. Almost done lol
10. Exit the game and if you backed up any setting e.g. Controls.con now is the time to paste them back
11. Now try and join a multiplayer server
The game should now work OK, but if you get kicked by punkbuster try these two programs
pbvc.exe pbsetup.exe
Please note:- that the above information is for Windows XP and is for guidance only, the above should not cause any harm to your system however, TBK cannot be held responsible for any loss or damage caused.
http://www.tbksquad.com/index.php