Sony player dvp-cx850d won't read cd or dvds. need to reset

This is not a problem that a reset will resolve. If you can gain access to the lens, try cleaning the lens using a cotton swab and alcohol. If that does not resolve the problem, the spindle motor may be defective. This is the motor that turns the disc. Once a disc is recognized as being loaded, the disc is spun up. If it does not get to speed fast enough, it will fail to read.

The bottom line is that without seeing the unit, I can not state exactly which scenerio you have here.

If the cleaning does not resolve the problem, I would suggest you request a detailed estimate from an authorized Sony service center.

Dan