Get the latest application compatibility from Microsoft. After you run it, then create a shortcut on your desktop for the application that you are trying to run. For eg: The application has a setup program that fails when you run it. Create a shortcut to the setup program. Right click on the shortcut and go to properties. One of the tabs will say compatibility. Choose Win95, Win98 or NT 4.0. If it then installs fine, great, have a nice day. If it doesn't, then I am out of suggestions.
Ed