tb said:
Thanks, Paul, for the very informative answer. I really appreciate
your efforts!
Of course I will make sure to backup all the important files before
doing the install.
What I would like to do initially is creating a dual-boot setup with
Windows XP and Windows 7. Windows 7 would reside on a different
partition than the one used by Windows XP. (Just in case things go
wrong with Windows 7. Later, when I know that things run smoothly, I
would delete the Windows XP partition.)
The version of Windows 7 that I will be using for the install is
"Windows 7 Home Premium _Upgrade_ Family Pack" (since I have two
desktops with Windows XP on them). I recall having seen back in 2009
several articles detailing tricks on how to do a clean custom install
on a partition other than the one where Windows XP resides using the
_upgrade_ version (as opposed to the full retail version) of Windows 7,
thus preserving Windows XP in its partition and creating a dual-boot
PC. I also seem to recollect that Microsoft tolerated this for a
while, but then they did something to the install files which would
prevent this kind of action. I think the whole issue was about
licensing rights and how the one for Windows 7 Upgrade did not allow
Windows XP to be on the same computer...
Am I remembering correctly?
I recollect someone mentioning you could install the upgrade
version, then install over top of it. Something like that.
What I can't tell you, is what will happen to the adjacent
WinXP partition while this is going on. I presume in each case,
you can point Windows 7 at a target partition, and that
is the one that gets zapped.
I certainly haven't tried it. Back when the test version of
Windows 7 was out, I did do a multiboot in a virtual machine,
with Windows 7 and WinXP, but I haven't done the "double
upgrade" thing you're trying.
The one thing you're doing, which simplifies matters a bit,
is installing Windows 7 after WinXP. So at least there is
a good chance you'll get a working boot menu, and fewer
additional steps.
In terms of the things important to WinXP, that would be
the entire C: partition (file system and Partition Boot Sector),
as well as sector 0 (the MBR). Backing those up, might preserve
your setup for you. That is, if you're trying to do this with
one disk. The MBR can be backed up like this:
http://www.chrysocome.net/dd
dd if=\\?\Devoce\Harddisk0\Partition0 of=C:\rainy_day_MBR.bin bs=512 count=1
The "rainy_day_MBR.bin" file will be 512 bytes long. You
can put it back, by reversing that command (of course,
that only being safe, if the partition table hasn't changed
since you did the backup, which usually isn't true for very
long).
If you know how to do "fixmbr" in WinXP, then backing up the
MBR is optional.
The way I'd do it (or try).
1) WinXP is in one partition.
2) Create a 30 to 40GB NTFS partition next to WinXP. Windows 7
has two ways it can install, a wasteful "dual primary partition
way" (my laptop is set up that way by Acer), or a more economical
single primary partition way. You'd want the latter, as you're a
multibooter, and primary partitions are a precious resource
(max four of them).
As far as I know, if you prepare a partition in advance for
Windows 7, and point the installer there, it's possible it
won't create one of those goofy "100MB boot partitions"
(like on my laptop).
3) Now, back up WinXP and back up the MBR for easy repair.
Since you've (hopefully) defined a useful partition setup
at this point (WinXP and Windows 7 primary partition), then
backing up the MBR will preserve the primary partition table,
complete with the size information for both partitions. That
way, restoring it later, won't cause a disastrous loss of data.
4) Do the first install of Windows 7. The upgrade will either
recognize your existing WinXP as a valid pre-requisite and
you'll only need to install once. Or, you can try the
"double install", which involves something like not activating,
and installing over top. (I'm not sure of the details on that,
so you'll have to use your Google Fu.) If your DVD in hand
was Windows 7 SP1, then who knows whether that dodge still
works.
5) If all is well, on the next "real" reboot of Windows 7,
the boot menu should show two OSes, Windows 7 and WinXP.
The Windows 7 BCD will "own" the boot process, and
hand off control to WinXP on request. If you ever
delete Windows 7, you'll have a bit of repair work
to do, so WinXP can boot. For example, that MBR you
backed up, assuming the primary partition definitions
haven't been changed, could be copied back. Or, you
could use "fixmbr" from the WinXP recovery console.
If the boot menu does not contain a WinXP entry for
some reason, you have the option of downloading
EasyBCD and fixing it. When I did my virtual machine
test case, I also got to test EasyBCD. Seemed easy
as pie, at the time.
HTH,
Paul
It's an unusual