MacBook 10.4.9 loses built-in sound when updating

Hi everyone!
I have a little problem with a black MacBook and that is that every time I try to update her from the 10.4.9 she came with, to a 10.4.11 or 10.5.something, the internal built-in speakers and mic stop working. If I go to system preferences, sound, they are just not existing anymore. And if I hit the volume button I get the full sound bar and a crossed circle. Nothing.
So then i get the old installation dvds out and start from zero and they reappear, safe and sound, and old school.
I went to the Mac store and they have no clue as to what it could be.
Anyone any suggestions!!!???

Thanks!!!