Help- Microsoft Office Problem

Having a "borrowed copy" of Office on my PC, I downloaded Silverlight (Microsoft program to view a website), & ever since then, cannot access MO.
I cannot do a System Restore, as it won;t allow me to go back to a date & time, other than after the event
Sny clues as to how I can unlock MO?
I cannot do a System Restore, as it won;t allow me to go back to a date & time, other than after the event

Sny clues as to how I can unlock MO?