So, sometime last year I tried installing Ubuntu 10.04 on my PowerMac G5 with the Live CD, and all I got was a black screen after i pressed enter on the boot screen, even when using 'live video=ofonly'. I tried using the Alternate CD, and i managed to get... somewhere. It installed absolutely fine, but when I came to starting it up, all I got was a blank screen, sometimes with a cyan-coloured cursor. I could still access the terminal, but when I tried to switch back to the GUI it just froze for about a minute before leaving me on a blank screen. I tried all sorts of workarounds, but to no avail. So, I uninstalled it from my Mac OS 10.5 install disk on disk utility and got rid of the hidden partitions too. It worked fine for a few days, and then i started to get 'kernel panics', where everything would freeze and the fans would just fly to full speed, causing me to force shut down. This continued until one day, it just wouldn't boot at all.

Anyway, I only just got round to finally fixing it today, although it was more of a lucky fluke than 'fixing'. Everything was working fine, so i decided to try Ubuntu again, only this time with 12.04. The HD is already partitioned so that half of it is empty. I put in the live CD, and had to use 'live video=ofonly' to get it to not black screen, but when it finally did boot after about 2 minutes of the monitor flashing between being on and off, i finally got the same cyan cursor as last time, and after waiting a little longer, the desktop turned up, only everything was cyan, there was no background and the sidebar was missing, but it was still responsive. I tried to get to the display settings but when i clicked it everything just froze again and I had to force shut down.

Is there any solution for this? I don't want to try forcing it to install it through the Alternate CD again, as that really messed up my computer last time, but if there is any solution please let me know!