Welcome to the forum.
Does RH appear in the list of programs in Add / Remove? If it
does, then try uninstalling there.
If not, do you have a System Restore Point to return the
registry to where it was before you started the installation?
Always wise to create one first. After you have rebuilt a few PCs
because you didn't, you soon remember that stage.
Beyond that, you could try
http://www.revouninstaller.com
Not tried personally but someone did report good results. If you
are unsure about using such a program which does edit the registry,
go cautiously and get expert help. Do you work with developers? Get
them to help if you can or someone like that. Don't be too daunted
if you don't have such help as I think RevoUninstaller creates a
System Restore Point so that you can get back to where you are now.
(At least you will be no worse off)
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