Instructions
Visit the Microsoft Download Center (see Resources) and download and install "FSX" related downloads to update "Flight Simulator X Deluxe Edition."
Click the Windows "Start" menu. Enter "dxdiag" in the "Search" box. Click "dxdiag" under "Programs." Click "No" when Windows asks to check for WHQL digital signatures, because they're not needed for the information you're going to look at.
Look at the "Processor" and "Memory" information. Make sure your processor is at least 1.0 GHZ and that you have at least 512 MB of RAM memory for the Windows 7 operating system.
Click "Next Page" and look at the "Device" information. "Device" is your video card. Make sure the "Approx total memory" is at least 32MB. Your video card must also support DirectX 9. Unless your video card was built earlier than 2000, it supports DirectX 9 and probably has the necessary memory. If your computer's processor, memory or video card do not fit the requirements, the game will not start until you upgrade your computer.
Reinstall the game. If the game will still not start after updating your computer and confirming that your computer fits the game's specifications, reinstalling the game will usually fix the problem. Click the Windows "Start" menu and navigate to the "Control Panel" and click "Uninstall a program." Select "Flight Simulator X Deluxe Edition" from the list and click "Uninstall." Follow the on-screen instructions to remove the game. Reinsert the game disc into your computer's disc drive and install the game again.