After every shutdown volume level goes to level 20 irrespective of what level of volume I've set before shutdown.What's wrong in there...i'm using w7 ultimate
Another problem is that some rootkit-like thing keeps working in the backgroung and conflicts during shutdown. Even eset smart security is not identifying the problem
If i was you i would install Avast 5 and run a boot time virus scan to find the offending issue. Mayber then you can begin to get to the bottom of your problem.
I'd uninstall the soundcard drivers and reinstall them. I think maybe you have a bad driver which takes control of your volume and also possibly causes problems at shutdown. Just a stab in the dark, but this would be my first step. Edit: an afterthought: have you set your sound card to "do nothing" when you receive a call? Windows can automatically reduce your volume when it detects a call.