Also disable functionnalities in unable/disable functionnalities in windows update or programs and functionnalities in control panel (I let only internet explorer 9) and uninstall ms c++ redistributable in programs and functionnalities in control panel. I've underpast my 200 matches lost difference from 200 win, 400 lost until 3000-3000 since 2700 win 2900 loose. What else?!

Punkbuster uses the ports UDP 24300-24399. Good luck.

You can also install PnkBstrA with pbsv.exe on the site http://www.punkbuster.com/index.php?page=faq-cod4.php Follow on it the two sections under the section with udp ports, you can find this section by push the key F3 and search UDP. The two section explain how to put as administrator PnkBstrA and install the certificate and there is the link to download pbsv.exe for PnkBstrA. Then you can put the ip adress of the punkbuster website acces http://127.0.0.1 with the button sites in internet options in control panel, you precise this ip in the tabs confidentiality (authorize) and security (in the item trusted site, only). The ip is find on cod5 linked in the page home of punkbuster site when you click on punkbuster for admins, it's in one of the sections.

In fact, there is only three nat ports to open, for mw2, mw3 and punkbuster, in TCP and UDP both 28960, 27666 and 24300-24399.

To update punkbuster with games that said htm md5s do not match information, error, try later, you can add these games in fact (Bullet Run, Battlefield bad company 2, black light retribution, Battlefield heroes, Ghost Recon Future Soldier). Just put pbsetup for all windows games in the desktop, delete pb folder, then add games by browsing the folder of mw3, and check updates, it run finally. I play DOM with the two dlc, and cheaters aren't so numbrous and are banned/kicked after one party with it. I don't say there is no cheaters but it's reasonable and in way of elimination.

How to enable VAC:

1. Restore the pc without windows update.

2. Unpeer all folders by click right on it and check the unpeer options or in properties like the folder user in C:\, and within this folder by click right on the blank.

3. Quit the residentiel group in control panel and change options.

4. Uncheck windows functionnalities like xps, tablet, games. Let only internet explorer.

5. Repair steam each days with the steam installer, it take only 2 minutes, no need to download again your steam games when you repair with the installer.

6. Uninstall the maximum of programs, let only steam, steam games, realtek and graphic card manager.

7. Delete in program files\steam\steamapps\common\mw3 all files that you think, with their dates, they were changes by hackers and in properties of mw3 on the library of steam, verify the integrity of files.

8. Open on your modem and your firewall the tcp/udp ports of steam write on steam support web site. To open these firewall ports follow on microsoft web site the instructions. When it's ok, block with the same way the tcp/udp port 3074 because antimalware antibytes blocks it in the same time of all the ip blocked.

11. Clear all your mw3 files, verify the integrity in properties of the game in steam, launch the game, it make an install, quit the game, and put all files to read only.

12. Install the certificate of pbsvc then launch it, you can google pbsvc to download it on the official site.

13. Launch pbsetup and check updates like explain in this thread. because punkbuster is the worst nightmare of cheaters.

14. Put md5tool in your mw3 game directory and use cmd dos like explain on the official site, you can change 2048 by 5000 or whatever. Put the pbsvuser.cfg in pb folder of the game directory.

15. Open the firewall and your modem to allow udp ports 27666, 24300-24399.

16. You can enjoy to buy BO 2 and play MW3 a bit of time untill the next blockbuster comes.