Windows 7, Closing Laptop Lid Causes Volume To Automatically Reduce?

Just having a weird problem with Windows 7. When I am using earphones or my laptop speakers and then I close the lid on my laptop, it causes a great reduction in the volume of the sound output automatically.While the laptop lid is still open, the volume on all programs remains normal.However, when I close my laptop lid, it seems Windows automatically reduces the volume.Let's say I put the volume on my laptop to 40/100 units in the sound mixer. All programs I am using are set to use the volume the sound output device is using, so everything else is also at 40/100 units, including Media Player Classic.I am usually using Media Player Classic to play some FLAC music. I usually have earphones connected, but this issue recurs without them as well.

When I close my laptop, in about 2 seconds the sound volume will automatically reduce to 5/100 units in the Volume Mixer in the taskbar. This sound reduction also only applies to the program I am currently using to play music (e.g. MPC or iTunes, the two which I've tried so far).After re-opening my laptop, I check the Volume Mixer and it shows only MPC or iTunes sound output is reduced. The system device speakers will still be at 40/100 units volume.his is really frustrating, because I like to turn on some music,