As with many Dual2.0 REvA G5's, mine needs a new PSU as the current one is way too noisey. What should I do prior to taking the G5 to the Apple Store, specifically in regards to backup? Will all of my settings be wiped out? What are the chances of my hard drive being wiped? I'd back up the whole thing, but I only have 40gb free on my external drive. Any tips?