Can't burn a DVD-R video to play on player.

I have an old Sony 725 DVD player, Win XP, NEC ND 3550a DVD RW drive. 
My DVD player  has proven itself capable of playing DVD-Rs.  I have
some ISO files that other people have been able to burn to DVD and
watch on their player.  I have tried about ten different ways to burn
them but it hasn't worked.  I have tried Nero Burning Rom, Cheetah,
and Clone DVD using the various different settings.  I have followed
guides so am using the software correctly, I have copied the right
files, not chosen multi-seesion discs, etc. I have tried different
burning speeds.  The DVD player says "no disc", my PC can play it
using DVD playing software.  I have only tried two types of media - HP
DVD-R, and Tekdata DVDRW.  My PC has successfully burnt data DVDs.  I
have followed the instructions on the guides but the same thing
happened.  I want to try another type of DVDR media, but aside from
that, i'm running out of options.  thanks.

Hi,

I guess I can't "answer" since Im not a researcher, but I've seen this
problem many times, and it seems to me you are experiencing a media
problem.  Older DVD players are very fussy about media, I have an old
Sanyo DVD player that will not play any burned DVD media.  My first
suggestion to you would be to try a high quality DVD+R disc. + or - RW
discs are nearly a foregone conclusion in older players, but you may
find a high quality DVD+R or even a different brand of DVD-R disc will
work better.  I suggest a Taiyo-Yuden if you can find them, or an
Optodisc Acro Circle Super Grade DVD+R...both of these blank discs
seem to work well in older DVD players.  Another good brand to try
would be a high quality Ritek.

Since the disc plays on your computer, and your sony reads "no disc",
I'd give some new high quality media a try, and that should solve your
problem.

HTH,
elJedo

Thank you for your advice.  I looked up the compatibility list for my
drive on the NEC website, and today went out and bought the only one I
found which was Verbatim DVD-R Advanced AZO+ which is meant to be a
premium disc I guess. The store didn't have +R discs when I went, but
is this still worth trying - I have a couple of -R discs that work on
my player that other people have made that are very cheap brands. 
I've tried using it twice with Nero BR and CloneDVD, and it is still
failing - my DVD player also sometimes shows no text but an error of
"13.00 C".  That is the last option I can think of, so i'm really
looking for some ideas here.

You can also take a friends DVD movie disc and see which combination
of format (+ or -) and brand works in your player. Also, you can take
the disc you have burned & try it in another player, sometimes you can
try it in store players just to make sure it has been authored
correctly.