My problem is that when I was trying to install Nvidia drivers (some 301 version) on Ubuntu 13.04, it evoked a message
Ubuntu is running on low graphics
After the installation (I am repenting of that installation a lot :(), whenever I reboot my laptop it shows only command line version of Ubuntu 13.04. I could reinstall Ubuntu using usb-stick, but it could cost me loss of important data. I tried to copy my home directory using live Ubuntu through usb-stick, but I get a permissions error.
My problem could have multiple solutions such as
I can reinstall Nvidia or integrated Intel graphics driver so that I can continue with my previous installation and data.
I can copy the data to an external harddisk through commands (which I don't know how to do) and reinstall Ubuntu (which I know how to do :))
I can copy the data though live Ubuntu run through usb-stick to an external hard disk.