Larry, if you're running iTunes, my experience might be relevant.  I had a similar problem on my XP about ten weeks ago after taking the advice on Apple's iTunes web site to "correct" a registry problem that would present a "registry error" message every time I started iTunes.  This surfaced after an unsolicited iTunes "upgrade."

"The retistry settings used by the iTunes drivers for importing and burning CDs and DVDs are missing...  reinstall iTunes"

I found I could ignore the error and import CDs(?) but the message was annoying.  
The Apple KB post instructed registry changes in the values of keys named "Upperfilters" and "LowerFilters."  Making these registry changes suppressed the startup error but then the PC would no longer recognize CDs or DVDs placed in the drive.  Reverting to the prior registry settings solved this problem but caused a return of the iTunes startup errors.  In the last few days, iTunes issued an upgrade (no content explanation, of course) that eliminated the startup error messages, and left my CD/DVD working just fine.  Case closed.

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