Can you listen to the system careful to see if the cd is spinning? Are multiple CDs giving you the same error? When was the last time you cleaned the laser?
Can you check the laser position to see if it moves every time you load a cd. Open the cd cover and take the cd out. Try to press play and see if the system see no cd. Then look around the location of the laser. Load the cd and see if it will read.
To clean the laser, you will need to order a Lacer cleaner on the link below http://www.amazon.com/Allsop-56500-CD-Laser-Lens-Cleaner/dp/B00000J1QK
Ok, I am thinking that the system needs repair beyond what I can offer online. I would suggest you take the system to a local electronics repair shop for further diagnostics and repairs