In my experience, the question of why would you...? wrapped in a condescending attitude with derogatory language, is a reflection of the individuals need to belittle someone in an attempt to elevate them self. A direct indication of the insecurity suffered by an individual who's own self image...
There are master volume controls in Windows that can be configured. It's likely the master is overriding any attempted changes. Weed through the audio settings in control panel.
The best chioce for the home theater environment is a MB or sound card with DDL. I have the X-Mytique and it's everything I was after. Computer audio encoding comes in two flavors: Software encoding- accomplished by your systems CPU Dolby Digital Live hardware encoding is accomplished...