All deleting registry keys does is makes the computer forget where the xLights show directory lives. Uninstalling and reinstalling xLights never really fixes any problems no matter what any user might think. There is nothing that happens upon install that can fix anything. If you have a screwed up show directory then you should be able to rename (while xLights is closed) and then upon restarting xLights it will prompt you for a show directory, pick a clean directory. Also you should have tons of backup files for your show directory that you could copy back in. I've never seen a problem that required registry changes. I know someone claimed they renamed their show directory and it didn't help but I think you did something wrong.