Upgrading an installation of R

I have installed R 1.4.0 on Windows 2000 and would like  to
upgrade to the newest version of R.  I am scared of messing
this up badly and would like to know if I should:

- uninstall my current version first, or
- just install the newer version without uninstalling
the current version

Do either of these work?  If both work, which is
preferable? Will I have to reinstall various 
packages that I previously installed on 1.4.0?

I tried:
- the FAQ
- ?install and help.search("install") from R
- searching on the word "install" on the site:
http://finzi.psych.upenn.edu/search.html

but the first two came up empty and the last
gave literally thousands of hits.


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