The Run command should be on your START menu. If not, simply type in
Winkey+R
and press return, which will launch the Run dialog.
To expand 'hives' in the Registry, you just click the little triangular
bullet to the left of each heading (exactly as you would expand a message
group in a Newsgroup or forum).
To see Help topics for using the Registry Editor, click on the Help menu in
the editor and choose 'Help Topics'.
There are also some hints on the registry at the end of this article:
http://word.mvps.org/faqs/customization/registry2007.html