I can't install Fallout 3, why?

Okay, I have a Toshiba with Windows 7. I bought the GOTY edition which has two discs. I have installed just the first disc ,which is Fallout3, and played to the very end. And I was wanting to go back and install the second disc (expansion packs) but my boyfriend uninstalled everything, but "saved" my character supposedly. And now I am trying to REinstall the first disc and it will not let me. It will get to 'Menuvoices.bsa' then stops and displays an error message that says " Feature transfer error Feature: DefaultFeature Component: Fallout 3 File: D:\data2.cab Error: The request could not be performed because of an I/O device error". Any help is appreciated.