Thanks for all the help. Im waiting now for a reply from the bloke at Microsoft Support!
My system is:
PIII 500Mhz
128Mb RAM, 32mb Graphics
All worked fine until one day it went Pear shaped.
Got the Patch..no luck. Uninstalled and reinstalled as it says...NO LUCK!!
NE1 wanna trade this in for half an hour of real flying??!!