It appears as though your problem is something else (not the installer problem Tony just added into the FAQ).

To answer your question, I'd say you want to delete the entry, not change it. I'm not sure what it's looking for on Host 2a, but whatever it is I gather it isn't going to find it. If this is true, you're most likely going to have to do the uninstall yourself, which means deleting files and stuff in the registry.

It goes without saying that hacking the registry can do serious damage if you delete the wrong thing.I'm not sitting at a windows machine at the moment, but if you're not in a hurry I can PM you tommorow morning when I get to work with some specifics of where to look for this stuff. If someone else wants to jump in, of course, feel free.