Blu-Ray players have two lenses inside them, one for reading BR's and the other for DVD's. It looks like the DVD lens has become 'ionised' probably from DVD discs with dust on them.
See what you need to do is go down to the beach and get you some sand. Open the disc tray (or if it is a slot, hold it open with a spoon) and pour the sand into the player. Plug the player in, turn it upside down and switch it on. Switching it on causes the fan to spin for a split second which is enough to drag the sand through the player and de-ionise the DVD lens. Your DVD's should now play as normal and the sand will be removed from the player by the fan through normal usage. Hope this helps.