Download PunkBuster, pbsetup for all windows games, and place pbsetup folder unziped in the folder of your game, the same for pbsvc. The first time you launch pbsetup for pb updates, add game, you just have to specify all folders of mw3 in program files (x86)/steam/steamapps/common/call of duty mw3, then you click the button add and you check updates.
For add game, you add CoD4 for MW3 and WaW for BO2, You should add all folders of your game, each time there is a folder you add this folder with the appropriate game of the game engine.
Add to the pb folder of your game the manualy update of pbsec.htm, pbsecsv.htm, pbsvnew.dll corresponding.
Then download and install as administrator pbsvc.exe, And Run the services in task manager of pnkbstA and pnkbstB.
It's said that bans with pb are lifted without MD5 tool. So put md5tool.exe before the folder of call of duty modern warfare 3 and you open the cmd dos and type cd c:\program files (x86)\steam\steamapps\common then you type in cmd dos md5tool.exe "call of duty modern warfare 3"\iw5mp.exe 0 2048. It create a txt file with wordpad named pbsvuser.cfg that you put in pb folder, it done:
pb_sv_md5tool a 1.9.453 v "call of duty modern warfare 3"\iw5mp.exe SZ6030488 AT0 LEN6030488 123DFA99FDCAF19645EFAD5284BBE412
pb_sv_md5toolfreq 1
So a cfg is autocreate and you can change the number of bytes size SZ6030488 to LEN2048 giving LEN6030488 by copy/paste this size.
Launch PBucon.exe placed in pb folder, and type I Agree then 192.168. two times, then a login name and a password of your choice.
The pbsetup, pbsvc, pbucon and md5tool are found on the site of PunkBuster.
Also you can open your modem nat port with the adress 192.168.1.1 (admin, admin), with nat:3074, 24300-24399, 27666 in UDP.
