A new and unusual error I believe gents..

Hello Chaps..
Don't want to bore you with tech info.. Had Win XP 32 bit game ran fine.. upgraded to Win 7 64 bit (on same PC) Game loads.. I start a flight.. it loads.. then i can hear engine noise and control the plane.. but i can only see my desktop background.. I press esc and it goes to the Menu.. I cannot under any circumstance uninstall win 7 (long story) I have not found this issue anywhere on the net after hours of searching yesterday (sorry and bugger me if I missed it) any Idea on how to resolve would be much appreciated... my trigger finger is itching

Warm Regards and Thanks in Advance..

Jack