What files do you think you deleted? When does the error occurr (ex: on startup, when you try to back up files, etc...)? Would you be opposed to reinstalling your copy of windows? (If it's a fresh install it's not much skin off of your nose.) Where did you get this copy of windows 8 and was the acquisition legal? lastly, what are your system specs, just in case?
These are all questions that need answering before anyone can help you in any way.