"What is the best way to start verifying why this component no longer works properly."
The BEST way is to change the drive out. This fixes it quickly and costs the least amount of tech time in the shop that I suggest it first.
You can of course try a CD Lens cleaner, update the drives firmware, use System Restore, reload the OS and what CD recording software you have, but you asked for best...
Bob
Windows XP Pro
Ram: 256 Mb
Yesterday my CD-RW stop been able to WRITE. I can still READ with it, no more able to COPY. What is the best way to start verifying why this component no longer works properly.
Thanks.

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic