Trying to help my friend fix his pc. One day he turned it on and it said "repairing C drive". he didn't think anything of it and then his PC started acting up and eventually crashed. the next time he signed into his PC it told him that his whole drive was corrupted. windows repair will not work to fix it. tried installing a new copy of windows from a usb drive onto his other hard drive which is empty but an option to install windows doesn't come up. only to repair windows. when he selects repair windows it will get to 75% and then run into an error. i have searched the internet all over and cannot find a solution to this. please help. thanks.