basically USB devices (mainly audio ones) have been not functioning correctly with my macbook. i've been trying to fix it for months and no one i've asked has had a clue, not even a professional who i sent it to, he was completely useless. here's the problem: all of my USB audio equipment wont will work fine when plugged in for a few seconds and then will gradually get worse and worse sound quality until there's no noise at all. its NOT the audio hardware, that all functions fine on other comps Its NOT drivers or other software issues, i done plenty of reinstall inc reinstalling various versions of OS X as well as all obvious tricks like disk permissions etc . Its NOT a compatibility issue, it all used to work fine, one day it just stopped. its clearly affected by other, internal USB devices like the keyboard and track pad as a sudden burst of static happens when ether of these are used. the best advice the person i sent my laptop to was to buy a powered USB hub which, even though i was totally aware this would incur latency and was didn't really address the problem, i did anyway. didn't help at all. Someone must have a clue whats going on... please give me some advice because i'm at my wits end - i'm a musician and depend on this equipment. edit : also, another odd symptom is that USB devices plugged into the ports don't show up in system profiler... even when they are (semi) working.