Hi, Trudy,
The page at
http://www.mvps.org/word/FAQs/General/FilesToBackup.htm
describes which files you need.
As for "how", first close Word (and Outlook, if you use Word as your email
editor). Then you can use Windows Explorer, the Windows backup utility, or
any third-party backup program to copy the files. If you're going to do an
immediate reinstallation, it's enough to simply copy them to a new folder on
the hard drive. It's safer to write them to a second physical hard drive if
you have one, or to an external drive or solid-state USB ("thumb drive" or
"jump drive"), or to a CD-R disk, or to your ISP's personal web space. Use
floppies if that's the only removable media you have, using something like
WinZip's disk-spanning if necessary.
To restore, first finish the complete reinstallation. IMPORTANT: If you
didn't completely clean off the old installation, you'll find all the old
stuff (Normal.dot, registry entries, other templates you've modified, custom
dictionary) intact, because uninstall purposely doesn't remove things that
changed after the first installation. This is often what you want, but if
you're reinstalling to try to solve a problem you'll probably find that the
problem is still there, too! Besides, reinstallation is usually too
time-consuming, when all you really need is to rename or delete one or a few
files. See the first few articles in the Application Errors FAQ at
http://www.mvps.org/word/FAQs/index.htm before you do anything else.
Anyway, once the reinstallation is done, just copy the backup files into
their original locations and then start Word. If you recorded a macro to
save your settings, run that macro.