Game: Raptor

This should bean easy game question…..
I have a DOS game called Raptor: Call of the Shadows 1.2. It used to work fine on my 98 system but on my 2000 and XP machines, it does not work, not even in pure DOS modes, but it will in DOS and 98 on the 98 system.
I need this game in my life. How an I get it working?