Ubuntu 8.04 中看过youtube后再看视频或者音乐没有声音

i had this problem too when i upgraded to hardy. heres the fix:
open up a terminal and type:

sudo apt-get install libflashsupport

(or search for "libflashsupport" in the synaptics package manager, right click on the package and choose "mark for installation", then click "apply")



then restart.
that fixed it for me. ;)