Just a quick check for you. Open Device manager and select View menu and change it to "Devices by connect". Look through, expanding each and everyone of the items if needed, for any yellow exclamation marks are red icons beside a device. especially those dealing with sound.
If you think you may have been infected and malware is causing this problem, then please go to the Malware section
of this forum and follow the instructions at the top. Especially the Click Here
link. That will give you several steps that will help you clean up most of all problems by yourself. If at the end of the cleanup process you are still having difficulty, and you may not be, then post a hijackthis log in THAT forum.
Please be patient as the "Malware Forum" is a very busy place and a two or three day wait is not unusual.
If you are still having problems after getting a clean bill of health from the Malware Section, please return to this thread. Please do not post a HiJackThis log in this thread unless asked to do so and then only as an attachment.
To attach log, when requested, either change the .log extension to .txt, or put the log into a compressed (zipped) folder.
Please post back if your problem has been solved.