Hello,
It is a hardwear problem
On each computer OS it is slightly different ,
But you need to right click on your computer icon and get to your device manager ,
You might need to reinstall the particular CD driver for your particular CD rom!
By going to your device manager you will know , the serial and type of driver that you have !
Google all you need , it will be more useful !!!
Did you change anything ? Like add new burner ?
That could be it , but most likely your device driver :)