I have been having a problem with Ubuntu on my HP pavilion tx2000 laptop. I installed Ubuntu 12.04 last summer and dual booted it alongside win7 for months.
Back in November I was installing upgrades to software packages when I decided to update the graphics drivers. This resulted in me not being able to login. It would get stuck at the ubuntu dots splash screen. I purged the nvidia settings, installed xorg again and reconfigured lightdm but it did not help. So I then decided to upgrade the release to 12.10. This helped a bit, I could get to the login screen and login but the desktop was missing, no dash, no task bar, just my wallpaper. I tried to recongigure lightdm again and installed ccsm and checked the plugins regquired for Unity, which were all unchecked. Now when I boot I have just a black screen and no login screen at all.
Any help would be greatly appreciated. I have used for many years on different PC's but consider myself a beginner with fixing issues. I am confident in terminal etc but not familiar with all commands/ packages required.