Weather Stuck Again!

I posted about this previously but the suggestion of cleaning temporary files didn't work. So I reinstalled FS9 to fix it but the problem has now cropped up again. I wonder if it's related to XP Pro's system restore?As before, the weather is stuck at certain settings when creating a new flight. It remains the same (clouds/visibility etc.) even if I pick a theme, real world weather or custom weather. Once I'm in flight it reverts to this same weather type and I have to change it through the menu.There must be a file somewhere or a registry entry that I can delete or edit to erradicate this without having to reinstall FS9 everytime?Please help!Paul