How do I fix this problem related to dvd-rw?

Hello Friends,
I'm having a specific problem using RW DVDs. After buying & formatting the DVD RW, I'd written 2 movies on it. After writing, when I saw it on my PC, it was showing, but it did not work on my DVD PLAYER. So, I full-erased it and again wrote 3 movies on it. Again, the same problem. I thought there must be some fault in the DVD RW & so I bought another DVD RW, but the problem remained as it was. Then I bought a CD RW and wrote a part of movie on it. It worked on PC as well as my DVD PLAYER.

PLEASE HELP ME FIX THIS PROBLEM?

[NOTE: I don't remember exactly, but I think something around 1-2 years. ago, the movies written on DVD RW I had at that time, were working on the my PC & DVD PLAYER too. At present, I'm using Nero SmartStart for burning process.]

look if the multisession button is turned off.
it can cause some problems with the DVD being played on DVD players

some DVD players (the ones you plug into a tele) :P dont support all formats.