Right so, You wanna play Call of Duty: Modern Warfare 3? You don't have the money? Here's the solution.
Step 1: Open Steam or get steam, you NEED Steam for this tutorial.
Step 2: Go to Library, then near the search bar, go to "Tools" then find "Call of Duty: Modern Warfare 3 - Dedicated Server" Download it.(it's around 14gb so it'll take a while.)
Step 3: Download this:
[Only admins are allowed to see this link]Step 4: Copy all the files inside into your MW3 installation folder(default is Computer/Local Disk (C:)/Program Files/Steam/Steamapps/common/call of duty modern warfare 3)
Step 5: Run "TeknoMW3.exe", then click Settings and set your name and FOV, then multiplayer and then Start LAN/Online.
Step 6: Go to options, Dedicated Server, then Enable Server Browser to yes.
Step 7: Go back and press "Servers" then enjoy.
If you have any problems just reply to this.