Vista running older software applications ?

"Windows Vista uses Compatibility Mode that tells which software application is an older version"
One concern for Windows XP users is if their favorite software applications will run once they upgrade to Vista.
Luckily, Windows Vista uses a feature called Compatibility Mode which tells the software application that Vista is actually an older OS, specifically Windows 95, 98, Me, NT, 2000, or XP.
Here's how it works:
If your software application won't install, open or work properly, right click on the application's .exe file. Select Properties and then click the Compatibility tab. From there, pick the previous Windows operating system you were on (most likely Windows XP). If you're a system operator, you can set this up as an administrator to make it easier for your staff.

Resource:Cnet