When I try to put a scratched cd in my combo drive, it is not able to read it.?

Most of your Cd/ Dvd drives won't be able to read scratched Cd's you can try one of those cd repair tools from the store or you can try a trick my son uses... He rubs gel type non porus toothpaste on the face of his scratched Cd's he then washes off the toothpaste with hot water then he takes a "green" marker and uses it on the outer edge of his cd's. I don't know how or why but it works in his car stereo, Xbox (original & 360) dvd player and even his Pc. He does this with any cd that gets scratched and they work. Hope it helps.

As per the other answerers, scratched CDs are only natural to require professional buffing once in a while. I concur with that explanation. My other obvious theory is that the new CD burner is both playing and recording at a higher speed. Three years ago you bought for example, a 32x speed max write which is now efficiently 52x. When you burned the CD, it was at 32x. Picking it up to read at "max" speed may be negligable, but when you through a scratch into it, well it's gonna need to compensate the sync (or in your case - not). Hope this helps...