I have 2 computers with the latest build of windows 10, one and old Gatway laptop that has been upgraded from Vista to 8 to 8.1 to 10. the second machine is a self built desktop that I just ungraded from 8.1 to 10. I have an old program, Wallmaster.exe . originally written for xp I believe, on both machines. This is a wallpaper changer program and is designed to run on startup. My problem is that on the laptop it runs on startup and works correctly but will not on the desktop. I have tried to make the program settings the same on both machines, On the laptop the program is set to not run in compatibility mode and not as administrator and the shortcut in the start folder is the same. On the desktop, if the program is set to not run in comparability mode it will not load on startup but will run perfectly from the desktop. If it is set to run in compatibility mode for windows xp it does load on startup but does not run correctly (the wallpaper image will not change). I am whipped. I have tried all the usual options like Using task scheduler and making direct registry entries for the startup folder. I simply can't understand what the difference can be on 2 supposedly identical windows installations.Any suggestions on what I may have missed would be appreciated.