i have a powerbook g4 and the volume icon is not showing on tool bar, also when i go to sysytem Preferesnce/sound i see the mute is ticked and i cant untick it ...help

A quick diagnostic: look in the headphone port on the comptuer. Can you see a red light glowing? If so, let us know--that is a check for a problem that's relatively easy to fix and avoid in the future.

Hello,

To place the volume control back in the menu bar, click on system preferences, then sound and then click the 'Show volume in menu bar' If that's already active but your can't adjust the volume as your not getting any sound, do the following;

Reset the PMU: http://support.apple.com/kb/HT1431?viewlocale=en_US&locale=en_US

For later PowerBook, shut down, remove battery and power adapter. Hold down the power button for 5 seconds. Place the battery back in and plug in the PowerBook. Restart. (This is how I fixed my sound problem on my PowerBook G4 17")

Best of luck.