(Mac ibookG4)--Someone please help!!!

I opened my itunes as usual and wanted to adjust my volume,(F3 key) but it didn't work. I tried adjusting the volume in the Control panel as well as made sure the (F1,F2 box is not checked), I know its usually not. And its still not working. While I am using Firefox, the usual volume key reloads the Firefox page instead of adjusting the volume. The contrast button is not working at all. I have no idea what to do, both volume and contrast only works if I manually changed them through the control panel

What I have done so far to recover:
I did the shutting off, taking out battery, and holding the power button (Didn't work)
I also did the Control+Option+P+R and that didn't work either.
I also tired the RRAM and no hope!!!!

I am sorry I don't know my about macs and I really would like to solve this problem asap. I had my ibookG4 for almost 5 years and never had a problem till now.

Thanks in advance!