Sound not working

A while ago my headphones started only working out of ear. My mac has been a bit beat up as well.

A few days ago some chip powder spilled on the mac, but only on the right side, away from the charger, headphones, and one of the USBs.

Yesterday I tried watching a video on youtube, and the video would load the images, but the circle would keep spinning, the video sound would not work, and the video would not play.

Today I tried to fix this by restarting my browser, then restarting my Mac. After I restarted, the sound icon at the top turned gray, and no sound is working.

I went to settings, and it's permanently mute.

I can't slide the button or click the mute box to unmute it. I can only hit those 3 check boxes. I do have the administrator account, but there's no lock box to unlock sound settings.

I can press F10, 11 or 12 and the sound box will show up like this:

if I press F10, or this

if I press F11 or F12.

Also, I tried accessing Mac Help and the Apple Store for an update, and neither of them worked. But my wifi is working fine and I can still access this website.