leopard and core audio help!!!!!!!!!!

i have a powerbook g4 1.5ghz with 1.25 gb of ram and have recently installed leopard. the first time i installed i i did an erase and install and around the 3rd or 4th time using my computer, my core audio driver started to not recognize. reinstalled the os, now back to the same thing. help!!!!

update, so soon ha.

i shut down my computer than restarted, and now the sound card is recognized again. i hope apple fixes this issue, its annoying.