go into safe mode and there
do a chkdsk /r /f
it should tell you that in order to scan the disk you need to restart
restart and it should bootup saying it will scan the disk for errors leave it there
it will take a few hours.....
just leave there
if you cant even load up to that point then follow here.... Startup Repair
follow this until you get to the system recovery options
go to command prompt then do a chdsk there....