Can't get update manager to update

Hey Im new to this and I have been trying to use the update manager and each time that I try and update it says "[I]Could not download all repository indexes

The repository might be no longer available or could not be contacted because of network problems. If available an older version of the failed index will be used. Otherwise the repository will be ignored. Check your network connection and the correct writing of the repository address in the preferences"[/I] how do i fix this?

I have a dell dimension 2400

hopefully someone can help me!!!

Thanks NIck

Check your connection and/or change Server

hi, go to Application > Accessories > Terminal

type

sudo apt-get update

and hit enter, type in your password and hit enter.

highlight the output and paste it on your next post.