mic input level not staying 'put'

I need to set the mic input level to 7 to have a quiet noisefloor for recording. But, it inevitably inches its way up to 10. How can I keep this set?

My first guess - shut down Skype.

If that’s not it, please tell us more about your set-up.
Which version of Windows?
Which exact version of Audacity (look in “Help > About Audacity”)
What are you recording?
What hardware are you using? (model numbers are good)
Has it ever worked?
Anything else that you think could be relevant?

I rebooted and the problem is fixed for now!?! I will let you know if it happens again. Thanks!