Well, with Windows 7 you can use Virtual XP mode to run applications (through a virtual environment) that do not work in plain W7. I haven't seriously tried it yet so I can't help further. And it depends on your CPU (does it support virtualization technology), and edition of 7 if you can actually run it. But this link should point in the right direction:
http://www.microsoft.com/windows/vir.../download.aspx