Windows NT or later? In other words, XP?
Start, Run, type ntbackup and hit enter. Not the most robust backup program but it's free and will backup a mapped drive. Whether it will backup directly to a DVD burner I don't know. Might have to backup to the hard drive and then burn. Hoops, but it would work if that is what you want to do, on a schedule and hands free. I imagine you could script the move from disk to DVD as well.