On the XP Hard drive version of the Acer Aspire One with an 8.9" screen, there are 19 screws required to disassemble the unit enough to replace memory. There are 4 different sizes/types of screws in this group of 19. Would someone please document where the short, medium and long black screws go? [The 4th screw type is the one silver screw that goes under the keyboard in the rightmost hole.]