At home I have my main PC: a notebook with Windows XP and tons of
programs, connected to the Internet via a 4Mbps/256Kbps ADSL.
At work in the office I have a secondary PC: a fixed PC with Windows
XP and my basic work programs, connected to Internet via an UMTS
384Kbps/64Kbps connection.
I often need to use my home main PC from work so I tried to use it
using Remote Desktop, at the usable speed of 256Kbps (the bottleneck
is my home ADSL uplink speed).
Using the remote desktop at 256Kbps is good but not sufficient for
prolonged use. I need more speed. I want to feel it like if I'm using
the local PC but moving my notebook from home to the work office each
day is not an acceptable solution because of the notebook weight.

MY IDEA is to move from home to the work office only my notebook HD
(120GB - 2,5") and "play" it, by attaching it to my work PC via USB
adaptor, inside a virtualization program like VMWARE.
I mean that I want to be able to boot the Windows XP that is inside my
notebook HD, seeing all its installed programs, from my work fixed PC
inside a (full-screen) window of a virtualization program like VMWARE.

IS IT POSSIBLE? is there a virtualization program (ex. VMWARE) that
can do this? if so, how?

note: I only accept a working solution as answer. If you don't know a
working solution please post as comment only.

Thanks

I have some experience working with VMWare and Microsoft's Virtual PC.
 I don't believe that they will do exactly what you are after.

For instance, lets say you install VMWare on your office computer and
hooked up your home HD to it.  You would be able to see the files
through your regular Windows Explorer, but not run the applications.
(But you knew that already)  Now you load VMWare.  To load a machine
into VMWare it must be a VMWare file.  When I machine is created in
VMWare it creates a single file whose size totals the amount of data
stored in your "virtual machine" (plus some overhead).  It must have
the whole Virtual Machine stored in that one proprietary file to load
it.

That said, one option would be to run your home computer as a Virtual
Machine.  Then you would have everything stored in that one file that
could then be opened through VMWare on your Office computer.  The
down-side of this would be that you would need to purchase two copies
of VMWare and you would have to create a new virtual machine on your
home computer and install all the software on it.

One more thought...  Have you gone through all the settings in Remote
Desktop?  You can set the connection type to a lower setting so that
it doesn't try to use so much bandwidth.  Open Remote Desktop and then
under "Options" and the "Experience" tab change your setting to 56K or
even try 28K.  Also un-check all the check boxes on that tab.  This
can make the connection seem faster.

There are other applications like PCAnwhere and RealVNC that are
remote connection utilities and may work better for you application.