when you upgraded, did you do a full install ( including formating and loading windows 7 up on a new partition or different Hard Drive ? )
when you installed Windows 7 then installed Aces High, did you install Aces High by right clicking the AHsetup.exe file and clicking run as administrator?
when you go to log into Aces high, try right clicking the AH shortcut/icon on your desktop ( or wherever you click on to run the game ) anyhows. try right clicking it and click "Run as administrator"
see if that helps you get past the problem.......
also posting the top 2/3rds of your DXDIAG report would might be of help also, if the above sugestions does not work.....
good luck