Cloned the harddrive in my HP Laptop running XP Home, with EZGig.
Switched harddrives. Now at startup, even though everything boots and
runs fine, am getting a 'Device installer error', which says 'Windows
could not load installer for volume. Contact your hardware vendor for
assistance'. Now this message pops up twice, probably for each
partition of the harddrive.

ALSO, when I connect the old drive through the EZGig USB enclosure,
get those two errors as well, and even though the HD is seen by
windows in Disk Manager, it will not assign a drive letter to it.

ALSO, when I did a Windows Update recently, got the above message, but
instead of Volume, it was for Keyboard, Computer, etc......

Make sure that you make the duplicate drive the primary drive
(master)?  Also, make sure that the drive partition is active - if you
didn't, then this is the solution to your problem!

You can do do this by using fdisk from a dos floppy.

some laptops have a partition that you won't see from within windows.
it's just a small thing, with some information on about your hardware.
this will need to be copied too.

Ok, supposedly, EZ-Gig cloned it so both HD's were identical. After
the clone, I switched drives, and turned on the laptop. Everything
booted, and came up fine, and everything runs OK, except now I have
this glitch......

I've heard of using FDISK /MBR, but unfortunately, I don't have a
floppy attached to this laptop, and I'm running WinXP Home. I CAN boot
off a CD, however, how to do this, and with what, on an XP machine,
w/NTFS file system eludes me..........z

i don't think you want to fanny about with fdisk /mbr. the fact is,
you clearly don't have a clone of the previous hard disk. try cloning
again.

That's a thought, however, I've reformatted/erased the original drive...

BTW, what is 'fanny'??????????? Thx, z

you must be american. does "don't mess about" mean anything to you?