Why it did not work for all three is somewhat of a mystery. It should have. One thing that comes to mind is perhaps Ad-watch still had a hold on the problem account preventing the reg change.
Might want to try it again with Ad-Watch completely disabled , make sure it's that way on all accounts.
I would prevent it from running at startup as well.
Is the account that you ran the reg files from the same one that's screwed up? If it is, log on to a different account and do it again.
The only other suggestion I have is to salvage what you need out of it , delete it, then create a new one.
As far as Ad-Watch itself goes, I don't care for it and don't use it. In fact, I don't use any Ad monitoring software at all anymore. It's just that I've seen Ad-watch do what it did to you a hundred times before.