erm... no....
Adjusting the volume in programs like Winamp, WMP, etc... is a standard feature, but really shouldn't be used to control the systemvolume of Windows!!! That is not the purpose of that control... For that you have your systemvolume control panel (or whatever you call it), use it....
If you have sounds in Windows, you'll notice that their volume will also be 'loud' compared to your Winamp soundvolume...
In other words, useless because the volume in MSN Messenger (and any other program for that matter (eg, like mIRC)) is controlled by your system en you already have a nice control for that (speakericon in your systemtray)...
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