Re: New USB sound card makes headphones way too loud!
That may help?! I've never used that or any other similar program for this type of application. It was listed for all Windows while...? no guarantees!
The alternative option you have left and might have to consider eventually would be replacing the present usb sound card you have now if nothing else works. I'm sure if you spent good money on a nice set of headphones you won't be trying out the Youtube instructions any time soon.
Desktop: cpu= AMD Phenom II X4 965, video = MSI Radeon HD 5750 1tb, sound = Creative XtremeGamer, memory = 8gb DDR3 1600, storage = 2 1tb OS sata II drives, 2 sata III storage/backup, 1 Sata II drive in usb enclosure, usb flash drives