Had this problem long time ago.
Here are a few ways to fix it :
1- You can fix it by simply plugging in a microphone or you can just plug anything into the microphone jack.
or
2- In the Activision folder, select Call of Duty 4.
Open your Miles Folder
Look for the Mssmp3.asi file
Rename it to Mssmp3.bak
or
3- Enable Stereo MIX, Vista RealTek
-Start, control panel
-Hardware and Sound
-Sound
-Recording Tab
-Right Click in window, chose "Show Disabled Devices"
-"Setero MIX"appeared, Right Click and choose enable
-OK
These fixes should fixed your problems.
I used the sterio mix thing
Originally Posted by Archangel
Had this problem long time ago.
Here are a few ways to fix it :
I used the sterio mix thing
Thanks that worked
sterio stupid thing lol
good to see your problem is solved
if you have any other questions, feel free to pm me