OK, I have been trying to put Ubuntu 8.04 onto my external hard disk (USB). So I plug it in, put in the CD, and go through the installation. After the installation I reboot and tell it to boot from my USB device, it works. I shut down and remove the hard disk, and boot up normally…only to discover GRUB error 21. It appears as though Ubuntu rewrote my MBR (Master Boot Record) onto the USB device, so I can only boot from the USB. What I had to do is reinstall Ubuntu, but before that, I had to pop in a Windows CD, go to the “Repair” sector, and enter the command:
It successfully rewrites the MBR, and I do a reboot, then reinstall Ubuntu. Everything works and my problem is solved.
Special thanks to my friend Logan for all the help, I appreciate it.