I am experiencing the same issue.
I've recently bought a new PC that runs windows 8.1.
In windows 8.1, my audio for my Samson C01U microphone is only audible at 72%. Below this, it is inaudible.
If I move the microphone to my windows 7 machine, the audio is audible at 4%.
This therefore rules out a hardware problem with the microphone.
If I use virtualbox, and assign the USB device to a virtual machine (running either Ubuntu, or windows 7), the Volume level works as expected within the virtual machine.
This rules out a hardware issue with the new PC.
In both Windows 7, and windows 8, the microphone uses the "Generic USB Audio" driver. This is provided by Microsoft.
This, therefore, means that the fault lies in the device driver, as provided by Microsoft.