My macbook's sound won't work - no output devices found in settings?

I've been having a lot of issues with my Macbook. It has a 2.4 GHz Intel Core 2 Duo processor and is running on version 10.6.8 Mac OS X. It asks for certification whenever surfing the web or loading websites, and always redirects to a different page. Now, the sound won't work at all - regardless of mute on/ off or sound turning up and down. I went to settings to check out the problem, and there is no output or input device listed or found on that page. I have no idea what's going on, and now, even though it's plugged in it won't charge.