In Windows 7 you do not need to format a DVD.
What is the format of the old video files?
Do you want to play the DVD in a standard player?
A program lije DVD Flick will convert and write movies to a standard DVD-R if your computer has a DVD burner.
http://www.dvdflick.net/The link above is for a free program.
Features:
Burn near any video file to DVD
Support for over 45 file formats
Support for over 60 video codecs
Support for over 40 audio codecs
Easily add a menu
Add your own subtitles
Easy to use interface
Burn your project to disc after encoding
Completely free without any adware, spyware or limitations
Recommended.