As far as your pc, I can't really say, you might want to call microsoft
support for your windows questions.

As far as your linux box (I gather you meant ubuntu 8.10, as there was
no January 2008 release) If you are using a firefox package from the
ubuntu repository, it is installed system wide, and individual users can
not modify it. To upgrade it, you need to upgrade it through the
repository. See this web page for details.

webupd8.blogspot.com/.../...tu-repository-deb.html

Then firefox will be updated quite often - several times a week.

If OTOH you want to discard the ubuntu firefox package and do it all
yourself, then just go into the synaptic package manager
(system->administration->synaptic) and remove firefox.

After removing the firefox package, you can download a firefox tarball
from firefox.com, and do things the old school way. Be sure and
recursively change the ownership of the installed firefox directory to
your user id, which will allow you to do the updates from firefox.com as
a normal user. Do remember to manually create and update all the
symlinks etc for your plugins. Other users on the system may or may not
be able to use firefox depending on how you set it up.

Why do all that when you can install FF via the Synaptic program.

Because he said he wanted to be able to do the firefox update direct
from firefox.com as an ordinary user, and that isn't permitted for the
ubuntu package, which is updated by the package manager.

I agree that synaptic is the way to go. I use the ff-3.5 and 3.6 daily
builds, from the ubuntu repositories and don't see the point of what he
wants to do.

Nevertheless, he asked how to do it, and I told him how, but also also
gave him a pointer to a howto on keeping it updated with synaptic instead.

Fire Fox is built into Ububtu kernel. If you remove FF, you can hose
the system. When there is a new FF version. About with in a weeks time. Ubie
will update the kernel and then FF.

Since when is Firefox built into the Ubuntu kernel? That must be news to
Mozilla, eh?

I call your hand on that - what verification, i.e. official Mozilla
documentation do you have, does Mozilla have for making that claim?

Uninstalling IE from a Windows computer (which bundles IE with Windows) is a
known feature, but that has never been a feature of Firefox/Ubuntu!