Boot CD, enter, install on på 250GB disk /dev/sda/, Grub error 7. Reboot, Repeat, Grub error 2. Repeat, reboot, start ubuntu, "Warning - /dev/sda1/ cant be found, dropping to a shell"

Can somone help me?

Welcome to LQ
I am not sure i will be able able to help much with this.
However for anybody to help you will need to post a bit more details
is your bios enabled to boot from a usb HD
What ubuntu version
What is the usb controller?
How far did the install go?
Where did you try to put grub? Was it on /dev/sda
Have you got any other distro installed?
How many IDE drives present?

Yes, my bios can boot from usb hd.
5.10.
USB2
From beginning to it says i need to rebbot and take out my cdrom
Standard MBR
No, but i have Windows XP installed.

In most distributions the USB modules are not included in the initial ramdisk (initrd). The USB modules are loaded after the kernel wants to mount the drives and so the reason sda is not found. You will need to rebuild the initrd to include the USB and SCSI modules.

I am not familar enough with ubuntu to know if the install CD has a rescue mode so you can access the drive. See man pages for mkinitrd for add the usb modules.

http://www.simonf.com/usb/

See SUCCESS - Breezy loaded on external USB drive
http://www.ubuntuforums.org/showthread.php?t=80811

I heard putting linux on a USB drive was not that easy...
But it is hearsay only, I do not know if it the case with all distros.
Plus, how does one define "not easy"?
Never tried yet, so learning as well

Let us know if the link helps

yayd, Have you got some linux experience?

HELP
I used that link, but it dont worked.
If i format my external hard drive, i get "Grub error 21", same if i unplugg it.
Now i just want to format my eksternal harddrive with NTFS, remove grub and Ubuntu, and use windows xp normally... How?

Sorry to hear that
>>I used that link, but it dont worked.
What does not? The link, or the method? at what stage?

>>If i format my external hard drive
With which utility?

I would imagine XP would wipe everything if you decide to use it as XP only.
I am not sure how you do the format with XP: right hand click on drive?

Sorry I cannot help much here

The metod, i done all, but then i should start ubuntu it dont works

I format with Norton Parition Magic.

error 21 : Selected disk does not exist
This error is returned if the device part of a device- or full file name refers to a disk or BIOS device that is not present or not recognized by the BIOS in the system.

Have you edited /boot/grub/menu.lst with vim?
If yes what did you write?
With the live cdrom you should be able to run a terminal
and edit /boot/grub/menu.lst on drive sda
and post its content to the thread (here)

It looks like grub is pointing to the wrong HD
(I am no expert)

If you give up and want to reformat evthg partition magice should do the job all right.
A bit soon to quit, but maybe simpler to had a 20 or 40 Go IDE internal HD for
linux and keep the 250 as a storage only for XP and linux

Im on a laptop, so my internal disk is only 30GB with XP and movies, music and stuff.

But its dont importen now, i just want to remove grub, i think i can do it later today (think i have a xp cd home)