lost audio control due to usb speakers

after connecting a CharWise C5 Laptop Cooling Pad with Speakers (Mukii INC.) I lost control over audio in my macbook pro. and some programs have no sound. the audio Icon is grayed and when I press the audio control buttons on my keyboard I get gray icon with the disabled sign on it.

I tried going to the preferences and select the internal speakers, it doesn't help.

also when I connect my headphoes and press the volume control I get the same disabled icon.

but I can hear sound in several programs like Adobe applications and vlc player. I get no sound at all in quicktime, iTunes doesn't play music and I can't hear sound from internet browsing.

the Macbook Pro is 3 months old. but I have no time to take it to the store as I need it to work.

Last time I updated my software through the App Store I got my audio control back after restart, next time I restarted I lost it again...

I'm using OS X Mountain Lion - updated.

How do I fix this?

how do I remove the drivers of the usb speakers?

please help