So in the last few days I've noticed that pressing my volume change keys actually isn't changing the volume on my macbook pro at all. When I press the volume up or down keys, it makes the recognisable pop sound but stays at the same volume while the squar

Question

So in the last few days I’ve noticed that pressing my volume change keys actually isn’t changing the volume on my macbook pro at all. When I press the volume up or down keys, it makes the recognisable pop sound but stays at the same volume while the squares go up or down. I mute it but my computer still makes sound. It’s the same with the volume control up the top of the screen, too. I slide it up and down and it doesn’t change the volume at all. The only way I can change the volume is with my speakers or the program I’m in (iTunes, VLC etc). I restarted and it seems to be okay then I go to change it a couple minutes later and it’s back to not working again.
I’ve checked my settings- the “use all F1, F2, etc. keys as standard fuction keys” is not switched on, and I have tried a suggestion of moving the com.apple.systempreferences.plist file out of the library and onto the desktop and restarting and neither of those seem to make any difference whatsoever. I’ve tried to find online forums but the only suggestions I found were those two and they didn’t work.
I’m just annoyed because I usually have the worst luck with technology but my macbook had been going strong and I got it because of the apparent lack of things that could go wrong, but of course even if there is one thing that could go wrong it will happen to me.
Please help!

Answer 1

You migh give resetting your NVRAM a try:
http://support.apple.com/kb/ht1379