1. Download a replacement Ntfs.Sys file from the System Files Home website. Also, download and install WinRar if you don’t have an unzipping program.
2. Save the Ntfs.Sys download to your desktop or “My Documents” folder. Open it with WinRar and unzip it to a folder you can easily remember.

3. Restart the computer in safe mode by repeatedly tapping “F8” before Windows loads.
4. Choose Safe Mode from the list of options and wait for the computer to completely load.
5. Locate the Ntfs.Sys file you downloaded; right-click on it and select “Copy.”
6. Go to 'My Computer,' then click 'C:,' then 'Windows,' then 'System 32.' Paste the file into the folder (right-click in an empty area of the folder and select 'Paste').
7. Restart the computer to see if the error reoccurs.