Ok, here's my situation. After I updated to OSX 10.4.8, my MBP started making the whine again, it has always done it even after getting the logic board replaced twice, albeit it's much softer than it was. Nevertheless, I'd taken care of the issue by using the PhotoBooth trick, but since all the the updates, I keep having to reinstall the IOUSB Family to keep the trick working. Anyway, after I updated OSX and the noise came back, I went to reinstall the old IOUSB and I installed the wrong one, so then my keyboard, trackpad, and mouse would not work anymore. I used the install disc and installed 10.4.6 but it kept my previous system and said that it would revert back to all previous settings when I updated the latest version of OSX. My question is, when I update to 10.4.8, will I my keyboard, trackpad, and mouse stop working because of my mistake with IOUSB, and if that's the case, can I just delete the "Previous Systems" folder before I update OSX?