when the cdrom drive doesn't read a cd i get this message in the Computer management...event viewer......system

Product: Windows Operating System
Event ID: 7
Source: Cdrom
Version: 5.2
Symbolic Name: IO_ERR_BAD_BLOCK
Message: The device, %1, has a bad block.

what the hell that means.....i don't know...

with other cdrom i can read the cd.....

thanks