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You're making it pretty difficult to add applications, etc, by using your system off line! Linux uses Repositories which are accessed on-line with a package manager like the Ubuntu Software centre or Synaptic Package Manager. You don't install them from CD as you might with MS products. Everything is accessed from the web. The package manager will solve any dependancies and add or delete your applications. Why do you want to update it off line? By not having it connected to the web you're losing one of it's major advantages over Windows software... i.e. All the software you want is in the same place!
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