Here's a configuration I'm testing with - so I know it can be done and I
don't see why it also would not meet the EULA requirements but I haven't
memorized the whole document yet either.... If there's any question here -
that would be it. The rest is just some ramblings that a few may be
interested in for their setup.

This test system has 3 Raptor SATA drives - nice and fast and all are
mounted in removal trays. I initially purchased 3 copies of Vista for
testing on my network but ran into some driver issues and whatnot, so my
testing has been confined to this one system for now until I get everything
else ironed out.

I started with a dual-boot configuration of WinXP Pro and Vista x64 on a
second drive. I activated the x64 version after two weeks and a shaky start
then I began some application testing. Ran into some issues with a couple
of app's that have not been ported over to x64 yet but will be in the near
future. Fair enough, the apps work under WinXP and I'm told should work
under Vista x86 and that's good enough for now.

I added a 3rd drive and install Vista x86 and start testing. I did not
activate this version until I tested what I needed. Everything is working
that "really" matters although there are some minor issues I'm finding
work-around for. But, I decide to stay with Vista x86 - so I activate it.
Since the key had already been used once for x64 version, I need to do a
telephone activation. No big deal and less than 5 min and an explanation of
why and what I'm doing - they say, okay here's the code.

I asked point blank If I can keep the x64 version in my now - multi-boot
configuration. Got the one PC, one license, one OS active speech which
sounded like it was being read from a script. Okay, I meet that criteria.
So now I have two versions of Vista that are both activated under the same
key on a single PC and it appears as long as it's on the one PC and only one
OS is active at any given time - it's legal. That begs the question about a
virtual PC environment which I've read is also legal - but let's not go
there tonight.....

I have done updates and other downloads under both versions that require OS
validation in order to do a download for some MS programs - and it worked
just fine. Now maybe the WGA will kick one of these out but the validation
server has the same "fingerprint" for each version so it really shouldn't -
technically.

It's not really practical for me to have 3 different OS's on one machine
and trying to keep them synchronized - and I really have no need for that
but I can see where some programmers and others may very well have a need
for this kind of configuration.

For me, I'll be slowly migrating over to Vista 32 bit but I need to keep
WinXP for some software compatibility in the near term. Once everything is
migrated to the 32 bit version, the 64 bit drivers and new software releases
should be ready for Vista x64 and I'll start testing and migrating to that.
WinXP will stay since I need to support some other networks that will not be
switching to Vista this year.

So if anyone is wondering - is it technically possible? Yes it is and it was
done using an upgrade version of Vista Ultimate. And my WinXP key is still
good, the Vista install did nothing to it since I did the clean install to a
different drive but to be legal, yes I have a copy of WinXP that has been
retired and the software removed from an old workstation - so I'm legal on
that point too.... We're subject to gov't audits and trust me you best have
all your software licenses or catch the wrath of an auditor having a bad
hair day.....

Just for giggles, I'm going to load Vista x86 on that old workstation before
we recycle or donate it just to see how it handles legacy hardware. It's a
P3 500MHz but I think I have an 800MHz CPU laying around if it won't accept
the 500MHz chip. Has 512Mb of memory (bare minimum for Vista) and a host of
drives from EIDE, SCSI and add-on SATA along with two CD/DVD combo's. Now I
don't expect it to run fast or nimble by any means but I was surprised as
hell when Vista recognized an old HP200 plotter I connected up to this
system. It will be just an exercise to see what old cards will or won't
work. We've always used name brand components in our systems so I'm
expecting to be pleasantly surprised that Vista will pick up on most of
these "mature" devices.

May come in handy for helping somebody else wondering if some of their
add-on cards and peripherals will work or not. Even have a SCSI interface
HP4C scanner on that system that has drivers for WinXP (amazing when you
consider I was using it on a Win3.11 box).

Bob S.