It looks like if you are mixing few things together.
NTSC and PAL are TV standards and it depend where you live for DVD player to play those.
NTSC region player will not play PAL DVD, unless you purchased special player.
If you are in PAL region, you are luckier, because most of those players will play both formats.
DVD-R or DVD+R depend on you, what you purchased at the store.
Some players are more picky at what format they play, but from your post it looks like you are using some cheap blank DVDs to record, that is why sometime they play sometime not. and dvd ripper or dvd to mp4 will also help u gay.

The titles of the 755 How-to guides but I didn't find this.
The issue is that sometimes I try to play copied DVDs in my DVD player and it doesn't play. Anothers yes.
So I want to know wich kind of DVDs I can't play. Are NTSC? Are they PAL? Are they DVD-R or DVD+R also http://www.dicsoft.com/how-to-convert-rmvb-to-hd.html

Can anyone suggest a software that can analize the DVD and give me all the information so I can see what's happening?

People always want to take audio from a DVD and recorded with camcorder (saved as a movie clip) and combine with pictures to make a slide show with me talking. But for me, I have Neuro smart start essentials and Windows movie maker. If anyone could point me in the right direction, that would be great! thanks so much!!!

But I find a very easy way to do this.Extract the audio from the dvd and convert it to wav.Found a video guides here: http://www.dicsoft.com/how-to-convert-dvd-to-wav.html

I just need a dvd ripperor a dvd to audio ripper ( it's cheaper than that ). Hope good for u guys.