Why are they both available? What can each one do that the other cannot? Which one should I use for getting rid of remnants of a failed "uninstall"? [I have used regedit on the few occaisions I have had to do that.] Just would like some further insight!

I've answered this question in here before so if you do a site search you'll probably find it but basically it goes like this. Regedt32 is the older version that is recommended for NT. It supports multiple string value which are multiple line entries in the registry. Something regedit does not handle well. Regedt32 also allows you to set security to certain areas of the registry. Regedt32 show all registry hives in seperate windows which many people do not care for. Regedit has more of an explorer view. Regedit has a better search function. For the most part it doesn't matter which you use. Usually if you 'need' to use regedt32 you will be doing so by following a technical article explaining what to do and they will usually recommend regedt32 if required.

Thank you.