I recently tried to install windows xp after tweaking it with Nlite. However when windows gets to the first authentication screen during install my product key doesn't work. It does work with the original windows disk (OEM XP pro), but not with the image Nlite creates. The only major change I made between the images was slip-streaming in service pack 3. This wouldn't be a problem except I need SP2 or later for this particular install. I've heard there are three different groupings of windows when it comes to product keys (OEM, Retail, Enterprise), and that they accept only keys from that particular grouping, but since the source files are coming from an OEM disk it seems like that shouldn't be an issue.