lock-up during upgrade
 

I installed mythbuntu 6 months ago and then upgraded it to the full ubuntu 10.04. I haven't used the MythTv portion of the install in about 4 months, although I never had problems with it.

After 5 months with no problems, I started having issues a couple weeks ago. My screen will just go blank after a few minutes of inactivity. It seems to just be the screensaver, but I can't get the desktop back. I have to do a hard reboot every time. I tried messing with the screensaver options and just turning it off but that didn't work.

To make matters worse, I tried to upgrade to 10.10, thinking that might fix the problem. It took about 10 tries to get all of the upgrade files because of the shutdowns. It then failed during the upgrade process and not I can't even reboot the computer. It starts to load Ubuntu and then says "configuration defaults for GNOME power manager have not been installed correctly". At that point I just get a black screen and nothing happens.

I'd like to know what was causing the black screen and reboots, but right now my main concern is getting anything to work. Please help. How do I get my system back. Thank you!

I would boot on an install cd, or if it will boot boot with init=/bin/bash as a kernel parameter

The latter gives you / mounted ro. check disks! Then mount and try and sort out your install, or repair it off the install cd. Back up anything useful