According to the [
http://windowshelp.microsoft.com/Win...f42dc1033.mspx ] Microsoft knowledge base article, compatibility mode is a feature of Windows Vista that allows you to run programs written for earlier versions of Windows, for example, Windows XP or Windows 2000. Many programs created for Windows XP may work in Windows Vista; however, there are some that may run incorrectly, if at all.
How to use Windows XP Compatibility Mode
To use Windows XP compatibility mode, right-click the setup application or executable (*.exe) and choose Properties from the context menu that appears:
Application Context Menu in Windows Vista
After choosing Properties from the context menu, a window will appear displaying the different properties of the application organized in tabs. Selecting the Compatibility tab allows for various, newer features of the operating system (Windows Vista) to be disabled when running this program. Additionally, the Compatibility tab gives the option to run your application as it is intended for Windows XP (Service Pack 2) or for almost all other previous versions of Windows, as available from the drop-down menu:
How to activate compatibility mode in Windows Vista
After choosing the compatibility mode for the operating system in which your application runs correctly, click Apply then click OK to save the changes.
If the operating system compatibility mode is not enough, try running the Program Compatibility Wizard by clicking the Start button Windows Vista Start Button , clicking Control Panel → Programs → Programs and Features → Use an older program with this version of Windows
If compability mode and the wizard does not solve the problem, check the program manufacturer's website for any updates or patches.