Playing DVDs I have burned/copied on my pc on any other DVD player?

I can copy and burn DVDs – no problem. They just will not play on any other player other than my pc.
I have just upgraded from XP to W7. I used to use DVD Shrink, DVD Decryptor, Nero 6 (Now not compatible with W7). I have tried CDburnerXP and some others. I do not seem to find a control to signify that the DVD is or will be ‘finalised’. I don’t know if this is the problem.
All I know is that I have 5 DVDs that are of the same original DVD, all play perfectly on my pc, but NONE will play on any other player!
Help??? !
Colinito