Many programmers design their software to run on a specific version of Windows. When a new Windows version appears a few years later, some older programs aren't compatible and refuse to work. If an older game or other program refuses to run under Windows 7, there’s still hope because of Windows 7’s secret compatibility mode. This mode tricks programs into thinking that they’re running under their favorite older version of Windows, letting them run in comfort.
If your old program has problems with Windows 7, follow these steps:
Right-click the program’s icon and choose Properties.
When the Properties dialog box appears, click the Compatibility tab.
In the Compatibility Mode section, select the Run This Program in Compatibility Mode For check box.
Select the program’s desired Windows version from the drop-down list.Compatibility mode lets you trick programs into thinking they’re running on older Windows versions.
Check your program’s box or look at its manual to see what version of Windows it expects.
Click OK and then try running your program again to see whether it works better.
Microsoft’s free Virtual Windows XP program lets you run Windows XP programs in their own XP-compatible window. Although it’s the most compatible way to run older programs, the program won’t run on every PC, and it’s kind of difficult to use.