try looking for system sounds under appearance. Took me a while to work out that beta set of 'aqua' sounds was the reason my mac was crashing on a regular basis. The built in platinum ones i assume should be fine but no harm in testing without. Might be conflicting with some other hardware in my machine but i'm only using built in audio and have no other audio devices apart from mic and speaker jack being used.

Well that what worked for me. Initially i was blaming the M$ mouse but was not the case even though its very buggy. I too had the mouse crashing thing from the chord.

Nother thing you can test if you have hte time and patience is just make a clean system folder on your machine and install the bare minimum of things to do what ya want and use that for a while. If crashing still occurs may look at the system software itself of hardware errors.

will