I got Ubuntu 10.4 LTS to install and run OK on an old Dell Inspiron, after overcoming an initial command line prompt and then foolishly upgraded to 12.x beta and that didn't see my home wireless network. So, I reinstalled back to 10.4 LTS, but now don't boot to GUI (as in first case) but get a "grub>" prompt in a command window. I have no idea of how to get the GUI to boot up. Help please. The initial installation booted to GUI OK, after an initial boot to command window. I overcame that with test install and then reinstall, though I got some out of disk space errors.
When the grub command prompt is shown, the grub config seems to be incorrect. You now could either try to boot manually by using the grub shell or you could boot into a rescue system and repair the grub config.
Please view this page for more information: http://www.linuxjournal.com/article/4622?page=0,1
This sounds a little bit like a /dev/sda vs. /dev/hda problem..