Make/Model of your computer please! Desktop or laptop? OEM computer (Dell, HP, Acer, Toshiba, etc.)? or Self-Built from parts you purchased? If so, full HW specs needed: Make/Model of Motherboard, CPU chip, GPU chip/card, RAM sticks, Hard Drive, and PSU Make/Model/Wattage. We can then assist you further by checking on your audio drivers being correct for your specific HW.
In the meantime, if you have all your Personal Data fully backed up manually or via Image Backup file to external media, you can attempt to
"rollback" your windows to a time when it was working properly using the built-in windows
SYSTEM RESTORE utility.
[if it was ever working correctly at all!?-see below] This often will undo driver damage from MS updates (used to be weekly, now monthly) or from virus/malware attack.
Last question: did your audio volume
EVER WORK CORRECTLY SINCE YOU OWNED OR BUILT THIS COMPUTER??? If not, a full W7 Reset or W7 Reinstallation from factory Recovery Media is quite likely in your near future.
This happens often when people buy used computers in yard sales or from sketchy online sellers on ebay or amazon.
If you bought the computer 2nd hand, and the audio never worked correctly, it's quite likely the seller sold it to you knowing full well about the problem, but not disclosing it to you in order to get your hard-earned cash and go buy him/her a brand new computer where everything works correctly: Including the Audio volume!
Post back requested information, and whether or not System Restore solved your problem. If so, you are good to go!
Best,
<<<BIGBEARJEDI>>>