Mac Osx And Flash Anims Sounds


My iMac G5 no longer reads sounds on the flash animations, neither can I hear the alert sounds( like incoming mails in Mail).
It has happened once, but I do not remember how I eventually fixed it.
It happened again after I had bought and downloaded music with iTunes and then burnt a CD to try and get wav files for an audio CD.
It seems as if Quicktime wants to read the Flash files now.
I have downloaded new Flash player,Quicktime player, Firefox.
I am running on MAC OSX 10.3.9.
Nothing gives.

Thank you