e-20 Message on CD player

I have a pontiac grand prix 2000, and the CD player starting giving me a E-20 message and won' t play. How do I fix this?

E20 is an internal Focus Error. Usually caused by humidity or dirt on the CD. Does it do this with any disk? If so you will need to get GM to service it.

E20 Focus Error Cause: The CD player cannot focus on the disc or there ia an internal focus problem, Correction: Try cleanig the disc or using a newer disc, Make sure the disc is loaded correcty. The road could be too rough or there is too much humidity.