failed to update - internet connection error

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http://askubuntu.com – i am using ubuntu 12.04 lts. i m trying to update but i get "Failed to download repository information Check your Internet connection." as error. My internet connection is fine. when i see details of the error an get this W:Failed to fetch http://dl.google.com/linux/chrome/deb/dists/stable/Release Unable to find expected entry 'main/source/Sources' in Release file (Wrong sources.list entry or malformed file) , E:Some index files failed to download. They have been ignored, or old ones used instead. any help please (HowTos)