All DVDs can play on Blu-ray Players
No, it will not play Bluray discs, but it is upscaling, so you can watch your regular DVDs at HD quality.
A DVD player cannot play a BluRay disc. A BluRay player can play both BluRay discs and DVDs.
Yes, BluRay DVD players also play non Blu-Ray DVDs with no problem.
No and HD DVDs have been permanently discontinued
No. All current 3D disc content is HD and so use Bluray discs. You have to have a 3D Bluray player.
Yes. Some Blu-Ray players can even play photo CDs and some can even display data on SD cardsAll players can, but not the very early ones (the first ones were manufactured in 2006)All Blu-Ray players can play DVDs and CDs
Yes, dvds can be played on bluray players.
A DVD player is a better decision than a BluRay player based on price alone. This type of player is cheaper. A BluRay player may be a better idea because it can also play DVDs and has more advanced features.
If it works on a DVD player, it works on a xbox 360
The Xbox 360 is not made to play Blu-ray DVDs. It will only play standard DVDs and this is likely the source of your problem.
No. DVD quality will be displayed whether the player is a DVD player or a Bluray player. DVDs won't be the same quality as a Bluray disc of course.
To play a high definition DVD, you need a high definition DVD player. There are two types available currently. HD DVD, developed by Toshiba is one and BluRay, developed by Sony is the other. They are not compatible, so an HD DVD will not play on a BluRay player and a BluRay disc will not play on an HD DVD player. BluRay looks like it is the winner in the format war between the two companies over the last years so it is likely that Toshiba's format will disappear in the coming months. Note that HD DVD can refer to the Toshiba format but it can also refer to high definition DVDs in general.