As far as the seal goes, have they placed a sticker over one of the screws? I have come accross this on numerous comps before. You can't open the case without loosening that screw, but you can't loosen the screw without putting a hole in the sticker or removing the sticker (it won't stick back on... trust me). If not, then they may have something inside that once you open it, it shows so, or that you would have to remove to get any real access to the parts.