Mustn't be that terrible, Gimpy. When I did a reinstall, I just went through your install routine again, but without uninstalling before. I just installed it again, over the old, and it worked. I did the above then, and had no problems since. I guess, the major problems come from the differing ways to handle dates and measurements. So, in America, you call that terrible date "Nine-eleven" - your order is Month/Day/Year. In a German mission, that day would be 11. 9. 2001 - Day/Month/Year.
It may also be, that distances make problems. When the game checks altitude in "Feet" above ground (zero), but the underlying Windows doesn't, your plane might explode at start, "thinking", it just ditched.
I don't know, if that is really so, as I'm not a computer expert nor programmer. But since I play with "Regional language and keyboard settings" all in English (USA), I didn't have any problems anymore, and enjoy Campaigns.
Oh, my god, it's 00:40 h here - good night, Gimpy, must work tomorrow!
Bye; Olham