Brian:
ALL registry entries have a default entry. And just so you understand...
When Excel (or any of the Office apps) run, they look for their settings in the registry (as well as a couple of other places). Specifically, Excel will look in that Excel folder you renamed. When you launched Excel, it did not find its folder in the registry, so it recreated it. That is what it's supposed to do. Hence, if there's any corruption in the Excel registry, we've wiped it out. But if the problem got worse, we could delete the new Excel registry folder and rename the old one from *OldExcel* back to *Excel* and when we launch Excel again, it would see the settings it had before.
Secondly, Excel looks first in a folder (on your hard drive--if you're at home) called XLSTART. Generally, unless you have a personal.xls file in which you store macros, there should not be anything in that folder. If you have Acrobat (not Reader, but the full version) or PDF Writer and certain other programs, they may have a file in there also. You can check that folder to see if anything is in it. If so, why don't you temporarily move those files somewhere else and see if the problem remains.
Thirdly, Excel will look in a folder that you have told it to under Tools-Options, General tab. If you have named anything in the box called *Alternate Startup Folder*, you may want to (at least) temporarily remove that as well. Many people confuse this with their default file location, which it is not. The *average* Excel user won't have anything in that box. If they do, they should know why, and how it affects Excel's operation.
I hope this sheds a little more light. Thorough troubleshooting of any of the applications can take many steps. To provide them all in one answer would take me too much time and I'd be able to help far fewer askers than I do now. This is one of the reasons I finally created my own web--so I can point people to information that I provide regularly without having to type it over and over.
I'll be here until we get this issue resolved. If you post and I don't respond, don't hesitate to PM me or email me directly to get me back in here. Without email notifications, I can be forgetful.
My shortfall in your issue is that I have no real experience with Windows XP. I have checked, however, and the registry is in the same folder as it has been since Windows 95.
One more thing. Find and rename your *.xlb file. It should be called something like brian.xlb somewhere on your hard drive--just do a search for *.xlb. This is your toolbars settings in Excel, and who knows---maybe there's something there. Just move the file to your desktop or something.
Any of my suggestions should be done with Excel CLOSED or they won't work.
Hope this information sheds some light, but even more, I hope we get this resolved!!