[Ponos]

I don't get the option to enable or disable the data files for these.....theyre installed too. only Anchorage shows up. do Pitt and BS require patches to run?

 

[McNinja]

To enable those expansion packs do this

open up Fallout Launcher
Data
and make sure those expansions are clicked

I would show you a screenshot of it, but it sems fallout launcher won't work but the game does...

 

[Tiber Septim]

Also check in the \Fallout 3\Data directory where the game is installed. Make sure there are files named something like 'Fallout.esm', 'ThePitt.esp' and 'BrokenSteel.esp'.
If those files aren't there, it hasn't installed correctly.