10.6.8 update Macbook Pro (2006) audio dropouts

Hi, I've got this nightmare problem, since I updated to OS10.6.8, my Macbook Pro late 2006 drops the audio, randomly, rendering the whole caboodle absolutely useless as a studio tool. It still works out of the headphone output, but not with my MOTU 828, or an M-Audio FW interface I tried it with either. Seems to happenw ith Logic, iTunes, whatever.

Has anybody else had this problem, perhaps suggest a solution? One Mac expert said he thought it was a firewire port issue, and nothing could be done without replacing the motherboard.

There was a wierd glitch with saving/storage afer 10.6.8 upgrade, and I used this fix..http://support.apple.com/kb/TS3968

Don't know if that could have affected anything..

Thankyou Mac world people.