After reading everything here, and looking at a few web sites, I came
across a blog in which an individual suggested running chkdsk with the /r
parameter. It took about two hours for chkdsk to do its thing, but when it
finished I tried the convert command again. This time it worked! I now have
an NTFS drive. Yippee.

I wonder if Starbucks will give me a free latte for doing that?
--
John H