I need help please!

My downloads reach 99%, 'saving' then say corrupted. I'm using limewire 4.0.8 and it seems to have EVERY file corrupt!? I've never seen anything like this. Its the same for mp3, mpeg files etc, nothing is a good file. Big co-incidence? (i tried to uninstall limewire, but it freezes during the removing and is unsuccessful)

Please can someone suggest a cure, i'm out of ideas