In a clean Windows installation, Creative THX TruStudio is not installed, unless you download and install it. It is only preset equalizer settings anyway. If you launch Realtek HD Audio Manager on a system without THX TruStudio, you will see a "Sound Effects" tab within the "Speakers" section. It is divided into an "Environment" section at the top with an "Equalizer" section on the bottom. The Equalizer section displays various preset equalizer settings - Pop, Live, Club, and Rock. But if you mouse over the button to the right of the "Reset" button, it displays "Change to graphic EQ". Click on it and a graphic equalizer with 10 adjustable frequency bands will be displayed.
There is nothing in the Equalizer section that would cause the volume to to change randomly during playback, however. I like @Myk's suggestion for that, but I can't figure out what Windows would be detecting as communication on your system to reduce the volume. It's supposed to change the volume only if you are using your laptop to make or receive phone calls.
In my Sound dialog, I have the default configuration to reduce volume by 80% when communication is detected and have never encountered any muting of music playback. Have you installed any 3rd Party communication programs on your system?
EDIT: I just saw your post made just prior to mine. So it's intermittent mute on reboot? Didn't catch that in your OP. Would it be appropriate to use a "You damn idiot!" here?
Check out suggestion #2 in http://answers.microsoft.com/en-us/w...3-f4d3687c5b77 and create a new account with Administrator rights, then attempt to reproduce your mute on reboot issue. However, if this mute on reboot issue is recent, then Windows System Restore (suggestion #1) would be the way to go.