Plays no DVD's of any kind or format

The disc may not be spinning when inserted into the player.

when you insert a disc, something holds it from the top and bottom and starts to spin it. If the upper and/or lower grips can no longer grip the disc strongly, the disc will not rotate or rotate very slowly or not in sync with the laser reading it.

to test this, put some double sided tape on the outer circumference of the middle hole of the dvd, don't go too close to the area where the data area on the dvd begins. do the bottom first.

if this works then you have to find a clever way of placing something on the grips so they can hold the discs stronger.

For my dvd player, i took it apart, cut a rubber sheet into a ring shape and glued it to the lower grip. Haven't had any problems so far.