what is wrong with my cd player?

Check for this simple mechanical problem. The CD player has to clamp the disc to spin it.With age the friction surface on the upper clamp can wear causing the disc to slip/skip during play. Using a paper ring on the CD upper friction surface (donut shaped ring area on side opposite of play area)should allow the CD to be clamped and played if this is the issue. Used to have this warm up issue with a Linn Genki before I opened it up and put some thin contact paper on the top clamp ring

thanks for your responses everyone

I would start with Davehrab's suggestion. Have you tried turning the unit off for ten minutes and then tryed loading a disc. If it plays and/or plays a portion of the disc then stops. I would say that it is probably the power supply for the transport or related components. If that doesn't reveal to be the problem then go after the dirty lens solutions suggested. You didn't mention what player you are using. Is it a drawer load, top load, or slot load.
If it is a drawer load you may want to remove the top and then use the canned air so that you can more directly aim at the lens. Same with a slot load. Hopefully it is something simple.