no need to back up hole system if you know what to back up.....
easy way to do is like this for you.....
open the terminal on your pc
you should see
:~$ if the screen show up like this u must login as root .....so to login as root
type sudo -i press enter
enter your passworld
you should see
:~# like this (pls note in first time if the terminal show all ready like this you dont need to do sudo -i)
sudo apt-get install sbackup press enter
pc will start downloading the packages then will ask you
do you want to continue y/n: y
after this will install all you need...
after open the
system-administration now you will see simple backup config
now follow the option and backup what you want ,,,,,you can backup only same directory's any time you want daily-weekly so on
or backup hole system is up to you
other option is
install on your other windows pc or laptop winscp program
this will allow you to login remotely no need you to turn on your linux pc monitor or not even you need a monitor attached to your linux server ....
login with winscp
you will see all directories listed in your server and all folder now copy what you want from there or what files you need just drag and drop to your desktop and keep it safe .....
so next time if same think goes wrong and you need to change the ubuntu version time to time
you can make a clean installation on ubuntu server using the life cd
after you can copy this files (wich is you copy with winscp to your windows pc before)
now you ready to go
i hope this will help for you ...