I'm thinking it's "there" but how could it be there and
not there at the same time?
Perhaps due to the way he did the install, he chose the
2nd drive. Perhaps the 2nd drive was formatted as FAT32
and therefore readable from a DOS prompt. I don't quite
understand, but there are other variables. The C drive
could be Hidden, but that would take some know how. It
could somehow be misformatted in such a way that it is
partially recognized as the C drive during boot, but then
the OS doesn't recognize it as a drive. Normally what
happens then is that D becomes named C, since C
is "missing". Normally the system drive that is booted is
C (where Boot.INI and NTLDR reside) but the boot partition
is the one where WINNT is located. I know that sounds
backwards. It's possible to have the boot start on C, like
even on a small FAT drive, then have the BOOT.INI point to
the D drive to load the rest of the Operating System in
D:\WINNT.
One more, some systems don't come with a Windows disk per
se but a "restore" CD that also puts a hidden partition on
the drive for BIOS or even for the setup files. That is
normally hidden and not even recognized, except during
boot up when "restore" might be an option key. What if
that were partially corrupted such that it claimed a drive
letter in error, but yet was invisible to the OS?
Just a bunch of wild ideas.