I have read (but not verified) that using XP video drivers on Win 7 will allow you to run DOS apps full-screen. You'll lose the Aero glass effects, though.
Running dos apps is easy with a program called Dosbox. Search for it, it is free to download and works great. It is also possible to set it up to run automatically when you open your program. Dosbox works on all versions of windows including Win7.