How to update debian
 

I used ubuntu for few months.yesterday i installed debian .Then i try to update .But it was failed.It says your system up to date. But i didn’t update it.Then i go to settings in update manager.
When i click it i got a window named software sources(as super user).It has several tabs. first one is debian software.there i couldn’t tick any one of three menu s under downlodable from internet
Under debian updates proposed update and security updates are in inactive stat.
I think i can only use cd as package source.how can i use internet to update my new system.

Please post the output of:

If you installed yesterday it will be upto date and there's no reason for it to update until, either there are updates available, or you add to your /etc/sources.list

If you had an internet connection when you installed Debian it is up-to-date.

As it downloads the current package versions during the install process.

If you want/need other packages or newer packages you might want to consider running either Testing/Wheezy or unstable.

There are also many 3rd party repos for Debian packages. See my Giant sources.list in my signature.

@craigvil your sources list is great it helps some of find a lot of info without googling til fingers go numb.
Ihaven't made many changes yet, but I'll ifnd 1 to make.

As supplemental information, Debian stable does not publish updates nearly so often as does Ubuntu.