Do you have more than one HDD? I am guessing here, but my guess is that you need to enter the BIOS and setup the RAID configuration, that is if you have a RAID configuration. See the owner's manual, chapter 4. https://downloads.dell.com/manuals/all-products/esuprt_desktop/esuprt_xps_desktop/xps-630_owner%27s%20manual_en-us.pdf