The other day when I install Ubuntu, and run LAMP, I get to install WordPress. I only use WordPress and work a lot on WordPress themes. However, when I changed back to user account, I cannot edit /var/www/ folder, not a bit. Even I use the Terminal to gain root access, I still can’t get it work until I find a way to manipulate root access – User Group.
If all you need is to delete a file in File System disk, you can use the Terminal command to gain root access by typing:
sudo nautilus
Then key in password. It will open main folder with root access. It is not recommend by lots of Linux user, mainly because not everyone familiar with Linux and once you go wrong, the whole system will be down.
Well, if you hate to use Terminal command, you can change system access to root only. Which mean once you login, turn on your computer, you’ll be as root (you can’t change name though) and everything basically is adjustable. Strongly not recommend by the Linux community. I doubt that though. With no virrus attack, why bother?
Last option, do like what I did, which is similar to above mentioned method. I change my user into root group. So I gain all the root access with my name on it 
By going to System -> Administration -> Users and Groups. Click on your username and c lick “Properties”…
Then you’ll gain access to /var/www/ without the need to get root access to copy-paste.