Hi, Keith.
You've correctly identified the problem: When you remove the first physical
drive, it will take with it the "system partition" (Drive C

, which holds
the "system files", C:\NTLDR, C:\NTDETECT.COM and C:\BOOT.INI. Without
those files, the computer can't boot into WinXP.
It would be easy enough to copy those files from the old C: to the old E:.
You'd have to remove the System, Hidden and Read-only attributes first, but
that's not hard to do. Then you could physically remove the first HD from
your computer. You probably would also move the second HD to the master
position on the primary IDE cable.
That would leave you with two problems. First, there would be no "boot
sector" on E: - but you could boot from the WinXP CD-ROM and run FixBoot
from the Recovery Console to solve this. Second, E:\boot.ini would still be
pointing to the second HD (rdisk(1), since HDs are counted starting with
zero), but E: is now on the first HD (rdisk(0)) - but you could run BootCfg
from the RC to rewrite E:\boot.ini (or edit it yourself from WinXP before
physically changing the drive connections).
One final problem would not be a problem at all for the computer, but it
might be quite confusing for you: Your computer would have no Drive C:. As
I said, the computer wouldn't mind; it would be quite happy booting from
Drive E:. But we humans all have the mindset that the computer has to have
a Drive C: and that the most important stuff is always on Drive C:. If you
can overcome that mindset, you should be home free. Except for correcting
all the applications that will want to use Drive C: when you install them in
the future.
You could use a third-party program like Partition Magic to shrink and move
your Drive E: partition and create a new primary partition in front of it to
become Drive C:. That partition could be quite small; all the system files
total much less than one MB. If you choose to do this, do it first and move
those files to the new C:\, rather than to the old E:\. And be sure to mark
the new Drive C: as Active (bootable).
I'm assuming that your Drive E: is a primary partition on your second HD,
and that it is the first partition on that HD. If my assumption is not
correct, please post back with the full description of your disks and
partitions.
RC