GRUB overwrites the Master Boot Record of the hard drive, so there is
no "fixing", per se. I needed to rewrite the MBR back to the
original state.

Only problem was that HP ships their computers with a backup of the
original disk on a protected partition, they no longer ship with an
install disk.

So my option was to 1. blow everything off the disk. 2. Find an
install disk and run FixBoot.exe from the repair section of the
install software.

Option 2 worked. I borrowed a friend's Vista 64 install disk and
reparied the MBR, and GRUB is gone.

Unfortunately, the install on the USB drive seems to rely on GRUB to
launch. If I try to boot from the USB drive now, the startup crashes
immediately. So now I have to figure out how to get Ubuntu installed
on the USB hard drive, without messing with the boot on the main
drive, and getting me in trouble with my wife.

I'm not sure I would try with a USB drive at all and seriously doubt it
would work.

Why not use the wubi install and teach the wife about the duel boot that
will anyway boot first to Windows if left alone.

I put Ubuntu on a external usb hd with Wubi. It
allows me to dual boot either Ubuntu or Windows XP. I
also was able to delete Ubuntu from the drive when I
thought I would have problem getting online with it
until I found a good PCI wireless card, then I
downloaded it again. Only problem I have is the
msttcorefont error.

Oh no problems with XP either, and the computer is a
Dell.

That is a drive though and not a memory pen, still unsure how a pen can
be set up to boot.

Goto
cnet.com and they have a video on how to put linux on
a pen drive. I want to say they were using Unbuntu
also.

Ubuntu is great for me, I managed to attract a nice woman but nothing special
happened.
I managed to install Damn Small Linux on a pen drive and it is OK but I do not
use it. My Knoppix problem is solved, It ran wonderfully on a weak PC at the
office, Gentoo Linux and ROSLIMS ran OK, too and also got connected to the
Internet. I will try Deli Linux on Monday.
Please send me some info about Fluxbuntu. Can I run it from a live CD without
installing ?

I have an HP and the same problem. However, if you write grub to the usb disk
instead of the mbr of your hard drive, it should work. With my HP, if you press
ESC at boot up then you can choose which drive to boot and if the usb dsik in
connected previously it will boot it you choose it from the list of devices to
boot.

I run Slax from a usb prendrive and grub is on the pendrive. I have also had
SUSE run from a usb hard drive with no problem. It is important to write it to
the right drive. Ubuntu by default chooses the mbr of the first hard drive. I
used pendrivelinux.com to install it to the pendrive according to their
instructions and it worked fine. I did not have to do anything to get grub to
work. There are ways to do it from Ubuntu's Live CD, but I have company all week
and I have very little computer time (which will probably produce some sighs).
Sorry to cop out on you.

If you have a modern bios (or an update to your bios) you may have to
reset the boot order to put USB device on first boot then the remainder
as before.