DVD Burning not reading or writing

My parents have a dvd burner that recently stopped reading/writing cds and I dont know exactly what is going on with it. It is a Lite-On 1633S and uses the default windows drivers.
The drive shows up and appears functional for everything else. I have done spyware/virus checks, gutted the startup, reinstalled the drive in windows and am now advising a lens cleaning. If anyone has any better ideas for me to try then that would be great. Thanks!!

have you updated the firmware? do you have any disks that were burned with it before? does it still read them?