microphone will not work while playing on-line games

Can anyone help, I have XP>
Whilst playing World at War my microphone will not work. The mic works fine when I tried it on the sound recorder. I have updated my drivers on my sound card which is a Realtek (sorry I don't know the exact model). Has anyony got any ideas ?.
thanks

Alright heres what you do in game press esc then go to sound and voice then click voice on the left hand side then at the top click in the box that says enable voice chat then make sure enable microphone is checked and also under that make sure it says your logitech device rather then system default and if you want it to be just like vent at the bottom just make sure push to talk is set up press the box then press what ever key you want. hope this helps

MikeY thanks for the reply but I have tried to do what you say.
When I am in game and I press esc it list options when I click on that I can either go into sound or chat. In chat it only lets me enable chat nothing else and in sounds it shows volume controls but they are at maximum but it makes no difference. Do you have anymore suggestions ?. Do you know of any software I can use that I can make as default for my mic ?.
thanks colinji

You are hitting v while in gameplay ? Also you do have it checked in Winodws sound manager? Try udating your soundcard drivers that might clear up any issues!

Im just speculating because when i had XP and experienced similar problems w. mic's (realtek aswell) realtek drivers usually can playback properly but when i comes to some games that are demanding they barely meet standards for recording, so it wont really work w. your mic.

IF thats not the case your probably having some packet loss, check your connection and pingtest.net i think.