Hi, Sir Eddy.
Yes, ALWAYS put each installation of Windows/Vista into a separate boot
volume. By "volume", I mean either a primary partition or a logical drive
in an extended partition, and this can be on any HD in your computer. But
remember that the terminology is counterintuitive: The "boot volume" is
where the \Windows "boot folder" is installed, with all its GBs of folders
and files. Since installations should not share a boot volume, no more than
one copy of Windows/Vista should be in C:.
But no matter where you choose to put the boot volume, a few startup files
MUST go into the System Partition. This must be a primary partition (not a
logical drive), it must be marked "Active" (bootable), and it must be on the
HD designated in the computer BIOS as the boot device. For Win2K/XP, these
startup files are NTLDR, NTDETECT.COM and Boot.ini. Vista's startup system
has changed: There is the new file "bootmgr" (no extension) in the System
Partition's Root, plus several files in its new \Boot folder, which holds
the BCD (Boot Configuration Data). (Most of these startup files are Hidden
and System files, so you usually won't see them.)
If you boot from the Vista DVD to run Setup, it has no idea what "drive'
letters you have assigned already, so it starts from scratch, assigning C:
to its own boot volume (which may be C: or G: or X: in your WinXP), and then
assigning other letters according to its built-in algorithm. (So your old
familiar C: may become D: or X:.)
Many of us prefer to boot into our existing WinXP or Vista and use Disk
Management to create and format the volume that we plan to use for Vista,
and assign it the letter we want Vista to use. Then insert the Vista DVD
and run Setup to do a clean install from within WinXP. This way, Vista
Setup can see the letters that have already been assigned and will respect
those. You can continue to have your System Partition using the letter C:,
with WinXP probably also using C: - or D: or whatever it has been using, and
put Vista into V: - or whatever letter YOU choose.
In a typical situation, adding Vista to an existing WinXP-only-in-C:
installation, we might say that we choose to install Vista into V:. But we
must remember that, while MOST of Vista will go into V:\Windows, a few
relatively small but extremely critical Vista files will still go into C:.
WinXP's startup files will still be there (in C:\, not in C:\Windows), but
the boot sector will be replaced by Vista's boot sector, which will first
present the Vista menu at each boot. If you choose the "previous" version
of Windows, the BCD system will back out of the way and use NTLDR to boot
WinXP, or to present the Boot.ini menu if you have more than one previous
Windows version.
Dual-booting works well. At each boot, you'll first see the Vista menu. If
you choose "previous" before it times out, you will boot just as you did
before; if there is only one "previous" version, that will boot
automatically, just as before. If you (manually or by default) choose
Vista, then Vista will boot. In either case, you should be able to see and
use all your files, subject to any permissions or other restrictions that
you have (intentionally or not) put on them, just as before. Most
applications will need to be reinstalled in Vista, but their data files
should be fully accessible from either WinXP or Vista. A few applications
can still be run in Vista by simply clicking on their .exe files.
