Unit where I work are having issues with the NTuser.dat file name in the All Users,turning blue. Applications are then corrupted and PC slows down. with that other problems occur requiring the unit to be reimaged. Quick fix has been to delete the NTUser.dat and the user's profile. This does not always correct the problem. My questions are: What causes the file name to go from black to blue? What causes the applications to be slow or not to work or work properly?