Well, I will only give you help to please you if you're female, otherwise you're on your own (anyway you turn it) ;-) Anyhoe, it might be that your dvd burner is worn out, or it might be that the media you use doesn't fare well with your dvd player. What you can do is:
1. to try the dvd in a different dvd player.(a) If it works then the problem lies with your dvd player.(b)If it doesn't work the problem might be in your media. If that's the case, try a different brand of DVD and then try to play it back in your dvd players and repeat a+b.
2. If that doesn't work, either I would suggest you try burning your DVD's with a different burner (and replace the one you have if possible) because your burner might have worn out.