To reset your video preferences, if you can't get to the ingame screen, you can do this:
Go to the settings folder in your aces high folder (it's located in program files in the HTC folder) and delete the video8.cfg file.
This will force you to reset your video preferences when you launch the game. Set your video settings back to where you had them before.
Once you get that done you should be able to run AH again.
Also, post the first 3rd of your DXDIAG report here. you probably will need at least a driver update if you are looking for better performance, but it's impossible to get help unless the wizards here can see what you are running.
cheers,
RTR