Hi, AJR.
In a dual boot setup, Vista installs files, including a hiddden folder
titled simply "Boot" at the XP location
Not necessarily "the XP location". Vista writes a new boot sector and
installs its files in the System Partition. Many (probably most) users
misunderstand the terms "System Partition" and "Boot Volume" (or "Boot
Partition") because they are actually counter-intuitive. (Not Microsoft's
fault; these terms were inherited from way back.) For an explanation, see
this KB article:
Definition of System Partition and Boot Partition
http://support.microsoft.com/kb/314470/EN-US/
The MS dual-boot (or single-boot) configuration is like a "Y" or a tree.
The System Partition is the trunk of this tree, which may contain many
branches - although in most cases, there's just one. That trunk holds the
boot sector and the startup files. Each branch can be a "boot volume" for
ONE operating system. So we can have WinXP on one branch and Vista x86 on a
second branch (and Vista x64 and WinXP x64 - and others - on other
branches). No matter how many OSes are installed, the boot always starts at
the trunk of the tree and then, depending on instructions found there,
branches to one of the boot volumes to load the system installed on that
branch. (Note that the boot sector is the first physical sector on the
partition. It is NOT a file; it is outside not in the Root or any folder
and normal file commands can't touch it at all.)
When WinXP Setup runs, it writes the WinXP boot sector and startup files
(NTLDR, NTDETECT.COM and Boot.ini) into the Root of that System Partition,
and then installs the rest of WinXP into the \Windows folder on whichever
branch the user chooses. MOST of the time, the user chooses (or defaults
to) the System Partition, which is almost always good old Drive C:. That
makes it impossible to reformat WinXP's boot volume without also
reformatting the System Partition - and wiping out the startup files.
When Vista Setup runs, it writes its own boot sector and startup files into
the Root of the System Partition. If it finds WinXP's files already there,
it first preserves the WinXP boot sector in a new file in the Root
(Bootsect.bak) before overwriting it. It does not delete the WinXP startup
files, but adds Vista's own bootmgr file and \Boot folder alongside those
and creates the dual-boot menu.
To remove WinXP later, DO NOT REFORMAT Drive C:. Just boot into Vista and
delete C:\Windows, the boot folder for WinXP. That leaves the boot sector
and all the startup files (for both WinXP and Vista) intact. For final
cleanup, delete the 3 WinXP startup files and use BCDEdit.exe - or a
third-party program - to remove WinXP from the dual-boot menu.
RC
--
R. C. White, CPA
San Marcos, TX
(e-mail address removed)
Microsoft Windows MVP
(Running Windows Live Mail beta in Vista Ultimate x64)