Try a laser lens cleaning CD in the drive, and make sure the CDs or DVDs are clean and free of major scratches.
If that doesn't help....
Since both CDs and DVDs are CDs, if it is ONLY DVD disks it won't read, you may have a software problem that can be fixed.
If it won't read ANY CD, or ANY CD or DVD, the laser(s) for reading CDs or it's (their) circuits are no longer working, or if you haven't been fiddling with the drive's connection to the computer, something else major is wrong - get yourself another burner drive.
If it will read factory or manufacturer's pre-recorded ("pressed") CDs no problem there is nothing wrong with it.
Sometimes a burner drive cannot read a burned CD made in another burner drive properly (e.g. CD-RWs), and Pioneer CD and DVD drives are well known to be pickier about which burnable media (brands and types of CDs or DVDs) you use in them. See the manufacturer's info about which media to use in your model, and/or look on the web for reviews of your model where they test various media in it.
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If your model is an IDE DVD "combo" drive that reads and burns both DVDs and CDs and is capable of 16X DVD +R or DVD -R or greater, it must be connected to an 80 wire data cable, even if it is by itself on an IDE controller, because it is capable of UMDA 66. If you use a 40 wire data cable, it cannot acheive it's fastest speeds, and if your burning software still allows you to choose faster speeds, the drive will likely produce data errors, and when Windows detects too many of those errors, it will, sooner or later, force the drive into PIO mode, and the DVD and burning features will no longer work in that mode.
