Well, that's made things worse. I used the Windows Control panel to uninstall and reinstalled the Saab. No improvement. Then I tried to install the Hotfix, on each aircraft before trying to fly again. The Cargo variant crashed X-Plane as soon as I clicked reboot, and X-Plane crashed out when trying to load the program with the Cargo variant as the chosen aircraft (I use the splash screen so I can choose a different aircraft etc every time X-Plane loads.) Now I've just tried to update my rendering options, before a quick test, and X-Plane crashed out. I have to go to work now, so can't look at this again today. Thinking I should reinstall XP from scratch, update it, then install the Saab before I install any other add-ons. The only other Add-on I have is SkyMaxx v2. But lots of scenery, a couple of aircraft and airports. I am grateful for your suggestions. LJM