Most older software will run on Vista, but plenty won’t. Fortunately, Vista includes a system called “Compatibility Mode” that gives older programs a fighting chance to run on the new OS.
Here’s how to set it up.
First, find the executable for the program in question. If you can find a shortcut icon, right-click it and click “Open file location.” This will open a window and highlight the original executable.
Now right-click this executable and select Properties. Here click the Compatibility tab. Click the box reading “Run this program in compatibility mode for:” and then click the drop-down below. Select the OS where you know the program worked before (probably Windows XP (Service Pack 2), but it goes back to Windows 95). See the screenshot above for more detail.
Click OK to finish up and then try running the program. If it doesn’t work right away you might have to experiment with a couple of different options in the compatibility drop-down.
For more compatibility mode options you can run Vista’s compatibility wizard by clicking Start > Control Panel > Programs > Use an older program with this version of Windows. This offers the same settings as outlined above but in a somewhat simpler interface.
source: yahoo.com