Overlacing files are not skins! Overlacing is replacing existing system files and adding files. Most of these are made by employees in free time. I call them official because i received them from an Microsoft address after I sent a e-mail asking Collin (product consultant) an e-mail on the layout of Vista and what it would look like. He sent me an e-mail with an attachment containing an overlace file (.oce). You find the btlln.oce and replace with the attachment but backup the old file incase you have a version of XP that does not support the file or replaces it after you load it and does not save old settings (In newer versions, XP does not allow the file to be replaced and reverts the file back to the old file that does not contain old MS updates). Most of the time the file is saved as system and is not visible. You can find software that can view system files that are not visible and then replace it. Most of the time these replacement overlace files are made by programmers who does it during breaks with programming software. Overlacing files are not skins because instead of changing one thing, this file extracts files in MSDOS that completely change programs and the way they run. For instance, in paint, you can make html files, and in word you can make a website a temporary background to the document so you can get information off it and scroll the site for more info. The reason it is called overlace is because the file can install using existing files to make it much easier to download. Skins simply replace the files that make programs LOOK different.