My Lizzie walks carefully around the computer but so far not on it. We've only had her for a few weeks, so maybe she's trying to build my confidence in her so that I will leave it open sometime for her to check out the LOL cats while I'm away.
On this old Toshiba laptop, the sound off/on button is in a row of other buttons along the top edge above the function keys. My husband's Acer keyboard is quite different, and the one I have with the desktop that is not currently working is different in other ways. Even some of the function keys have different functions, which I find rather annoying. I hope you figured out where it is on yours.