Installing Python(x,y)

So, I installed Python(x,y) 2.6.6.0. just about a year ago.  It's been
working just fine.

Now, I would like to upgrade to the latest Python(x,y)...2.7.2.2

From what I remember, installing Python(x,y) was not the friendliest
thing.  As much as I appreciate Python(x.y) and its modularity, I
think I was still confused as to how exactly to go about it...at the
end, I opted to download the entire thing (very time consuming) and
installed everything (couldn't figure out or trust the module at a
time thing).  I also seem to recall not being able to get a working
Python(x,y) on the first attempt and being left without python for a
couple of days while I tried different installation order or directory
names or something.

So, I have   c:\Python26   and   c:\pythonxy   :

what's the best way to upgrade?
Is there a way to go about installing latest Python(x,y) [b]without un-
installing[/b] present installation?
maybe temporarily disabling present install?
just in case Python(x,y) does not work out right away?

Should I need to totally un-install present installation, do I need to
install Python 2.7 BEFORE installing Python(x,y)?

any other hints? warnings?

thanks