Sound volume controls on keyboard not working

System Preferences->Keyboard->Keyboard Shortcuts->select Keyboard & Text Input->Restore Defaults and restart.

In Audio Midi Setup in Applications> Utilities, check that settings for output are correct. 2ch- 24 bit/ format should be 44100.0 Hz.

If that doesn't help, you might also try trashing the com.apple.soundpref.plist in Preferences in the Library in your Home Folder. This one might be corrupted and doing this will automatically generate a new one.

Same problem here. I have 10.63 installed on a 320gb and the volume controls work. I installed a 1TB drive and put a fresh 10.63 on it but the volume keys don't work. No idea why...

Try system prefs/keyboard/keyboard/ and uncheck Use all F1, F2 etc as standard function keys.

Other wise the volume and brightness controls will only work if you hold down the function key first (fn)

Which "original iMac wired keyboard" do you have? If it is the full-sized white one with the transparent frame (Identified in System Profiler as "Apple Pro Keyboard" with a product ID of 0x1003), it doesn't have a function key & you won't see the "Use all F1, F2 etc. as standard function keys" option.

For this keyboard, the volume keys are not dual function, but they should still work as they always have with 10.6.4. (I just checked with mine substituted for the newer aluminum one I normally use, & the keys still control volume.)