External Microphone Not working... sometimes...

Okay so at this point it seems as though I have tried everything...

I have a fully functioning internal Microphone, works with everything, no problem!

But recently I have been experimenting with recording my voice with Game footage using the stereo mix etc.

I had it working fine, Game footage, Game audio and voice! Brilliant!

Voice was a tad quiet however so I thought I'd buy a better microphone just to improve slightly what I already had working excellently...

Okay so here is where it got annoying, If I open recording devices via the little speaker button by the Time on the task bar and I then plug the external microphone in, I see the levels rise and as long as that window is open I can record with the external mic... The second it closes NOTHING. Not even the internal mic... what the hell?

I am beyond confused, it is so weird. I unplug the external after the window closes and then the internal works... and the external won't even register unless I plug it in while the recording devices window is open, what on earth is going on... Any help with this crazy matter will be greatly appreciated!

Rich :)

I would just like to add aswell that I have tried all the muting's and level editing you can throw at me because I have googled this extensively before asking this question... The closest I got to a solution was some guy saying that external microphones acted as Line Ins... and to disable the Microphone and then use the external as a line in. Trouble is when I plug it in, it uses the microphone option in recording devices so its completely disabled... and nothing happens with line in... then i plug it into the line in... and nothing happens. Please help guys its killing me! haha