How to Turn Off Compatibility Mode for iTunesby David Weedmark
When opening iTunes on a computer with the Windows 7 or Windows Vista operating systems, you may get a QuickTime error message stating "iTunes requires Windows 2000 or later" or "Error 42003." Both errors request that you disable compatibility mode on iTunes. Compatibility mode allows some older programs to work on Windows 7 or Windows XP operating systems, but should not be used when running iTunes v 6.0.2 or later. Make sure you are running the most recent version of iTunes.
Click the "Start" menu and select "Computer."
Select the drive where Windows is installed. This is the "C:/" drive on most computers.
Double-click the "Program Files" folder. If you are using a 64-bit operating system, double-click "Program Files (x86)" instead.
Double-click the "iTunes" folder.
Right-click "iTunes.exe," then select "Properties" from the drop-down menu.
Select the "Compatibility" tab on the Properties window.
Clear the check box under "Compatibility mode" by clicking on it with your mouse. Click "OK," then open iTunes again.