I really am a complete noob when it comes to Linux operating systems, and I've looked everywhere but cannot fix this.
I have a laptop (Dell Latitude D620) which used to have Windows 7 on it, but it went to crap and a friend told me to try Ubuntu. She had a cd with 12.04 on it and it installed perfectly and the first time it booted to the desktop with no problems. I then did all the updates and the screen went black. I rebooted the laptop and it went right to the update window and asked if I wanted to complete the updates, so I clicked yes. It then completed everything and rebooted itself. From there is where the problems began.
It would show the splash screen with the Ubuntu logo, but after that the screen would go black. No login screen or anything. I could not even get to the terminal. I could reboot into 'Safe Mode' and get to a terminal that way and I searched many forums with similar-sounding problems and nothing helped. After what seemed like forever trying different solutions - I guess Ubuntu has problems with Nvidia graphics - I gave up and just re-installed it from the disk. I figured that I would just not update it and try to find solutions in teh mean time. The install worked and went to the desktop again.
Well I just tried to turn the laptop on again and it goes to the login screen, but after I log on, it just goes to the default backgroung with the mouse pointer, no menu or icons. I can get to the terminal and I tried many more 'fixes', but I cannot update anything. Running sudo apt-get update does not work, it just says Failed to Fetch. Another solution was to run sudo apt-get install aptitude gnome-panel gnome-shell (I guess that fixed it for many people), but it would fail the install. I have the internet cable plugged right into the laptop and it works on the other computer, just not this one.
Sorry for the huge post, but the more details the better. Any help would be great.