I have known about this issue for a while and as of yet I haven’t found a good solution (though, admittedly, I am yet to look for one!) and the reason as to why I’m posting this now is that I know I’m not alone in having this problem — I got two hits from someone searching “no sound macbook pro vista ultimate 2008″
The problem occurs randomly, but I’m pretty sure that I see it more after my MacBook Pro has resumed from sleep in Vista (Ultimate 64 bit).
The problem is that no sound will play out of the speakers even though the system is unmuted and should be playing sounds!
The only way I have found to get around this is to insert some headphones/speakers into the headphone jack and then remove them. This always restores the sound for me….. But, I will get on to finding out if there is a better solution than this and I’ll update this post if I find anything.
Does this work for you? Or have you found some other way to restore sound? If you have found another way, please comment.