Atom intel 945 motherboard audio issue

Solution
Dear friend please explain what you mean by tempos going up and down :)
a little more information about your hardware and sound card would be helpful.
Get into the device manager.
Goto your USB audio device which "pluy's and unpluy's (Whatever that means)" automatically and uncheck the power management of the rig.
Meaning there is a Box which says, Allow the Computer to Switch off this Device to Save Power, you need to uncheck that.