Will not play dvd s
I guess, this happens with every CD/DVD player - and the root reason is fine grain sticky dust on the lens + backlash of laser driver motor.
Please take this as a general guideline:
If possible, open the DVD player - not all DVD players are designed to have quick access to lens - however you can try.
Get a micro-fibre lens cleaning cloth - do not use any fluid - be very very gentle, while wiping the lens - and I am quite sure you will see dirts in the microfibre cloth.
I did so for 2 of my DVD players, one was bit expensive one from ONKYO - even with visual inspection, the lens looks shining and no dirt, when I rubbed [very gentle rubbing] with micro-fibre cloth [I got from Pro Camera/Photography shop - as lens cleaner] - I got good results.