I've a dual boot system with XP and Ubuntu. (Grub 1.5) Ubuntu was originally installed from a CD and has its own partition on an external hard drive.
After an upgrade from 11.10 to 12.04 the 3.XX kernel let me log in, but then give me a black screen. The 2.XX kernel give me a workspace, but with a distorted aspect. (I had to play with the monitor settings to even get the system button to appear.) I tried 12.04 on a USB and it looked OK, but was so slow I would never use it. What is the best way to reinstall 12.04 or even 11.10?

HDIO_GET_IDENTITY failed for /dev/sdb. I have gotten this message for a very long time without any adverse effects. Then I get the messagefailed to set mode in [CRTC:6]. I tried insertingnomodesetinto grub, but the boot still hangs after a few seconds with a blank screen. Nothing I do in recovery mode gets me any farther. The advice from Floyd is good, but no use until I get 12.04 to boot. What do I do next? – MPR May 30 '12 at 15:09