Files administration problem

i have a 2tb my book live unit, and i have 2 issues using the unit by internet:

*first i cant open directly any ms office file, that means i cant edit them… this make no sense because is one of the basic reasons of why people grab this kind of external units

*second, after i make a local copy of any ms office file and edit them, i cant replace the one at the network unit, i tried erasing and then copy to the unit, but that also doesnt work. i tried doing a reboot of the laptop and when i connect again theres the file, still on the unit without any changes. in the end, i cant make any file modification from the internet.

ill appreciate your help

thanks

What operating system do you have?

i have windows 7 home premium