Upload & Sell: Off
Also check the info on one of the .nef files and be sure it is as large as you think it may be.
Are you opening them, or importing them? Try importing.
Also, if you haven't done this, try rebooting your PC. On a Mac, I would repair the permissions. Don't know what the equivalent is on the PC.
You could also download the free demo of Lightroom, or Photoshop, and see if that works...