You said you have a 42" tv and it's not widescreen right?
So it must be a projection tv.
By my calculations, your tv screen is 25.2" in height and you should end up with a picture that is 18" tall if you are playing the most common widescreen DVD's(1.85:1). So the black bars should only be about 3.5" on top and bottom. If you are playing what they usually call an anamorphic widescreen DVD (2.35:1), you should still end up with a picture that is 14" tall.
Either way, if you're getting a picture that is "literally" 5" tall, there is something very wrong.