To murraysch
This is the response I typed yesterday but didn't post for a reason I'll note at the end.

"I think you have come up with the answer!

After a couple of weeks of frustrations, posts on four user forums, countless e-mails to and from Dell & W.D. tech people, plus a couple of phone calls and conversations with retail computer store personnel, I am now finally able to access my new Passport drive.

After experimenting with both cables and having the drive plugged in (and not plugged in) when booting up, I find that I don't need the power booster cable and the drive is recognized both ways.

Somehow during one of my experiments, I wound up with an extra "removable drive" in Windows Explorer, but using "Safely remove hardware" I shut that drive down and it didn't re-appear.

Thanks so much for your help. I only wish you had come on the scene a couple weeks ago!"

The reason I didn't post this yesterday is I had another question on another forum which I wanted to check out first - not that it would invalidate your solution. The other question was whether or not I had TweakUI installed on my computer. I do, and it was suggested that I check "drives" under My Computer to see that drive J (my Passport drive) was checked and that it didn't have a question mark over it. After changing the registry entry back to what it had been before trying your solution, I checked and found that drive J was listed with no question mark but it wasn't checked. I checked the box next to the drive and "Voila" my drive was now accessable!

It's incredibly ironic that after all this time and stress I got two solution one day apart! I'll post your solution on the other forum as well as posting both solutions on other web sites that didn't produce a solution - or even a response in a couple of cases.

Thanks to all of you who tried to help me with my problem. We all learned something!!