Problems with Microphone on iBook G4

hey everyone,
I registered just to ask this question everyone seems to know so much about macs unlike me
Ive got an iBook g4 and have no idea on how to make the microphone work...
I installed Audacity to try and see if i could tape something but it just comes up with like a kinda buzzing ringing noise I tried testing out the settings in system preferences-sound- sound input but anything i try never works. I have to do a presentation for school in the next couple of weeks so i really need it to work.
Any help, suggestions anything would be greatly appriciated!
Thank you
Tina

Fire up garageband and see if it works there..
Remember to set it as your input device under Garageband preferences.

Under system preferences, does anything show up on the sound level meter if you tap the pinhole microphone?
(System preferences>Sound>Input)