raw – Nikon D90 images have a nice appearance on the camera, but the NEF and JPEG format images appear on the computer in yellow.

It's probably a problem of white balance. NEF or RAW files do not yet have white balance adjustment. They are a recording of the data before parameters such as white balance are applied. If you load the NEF file in a viewer, assumptions about the use of the white balance are assumed. That's why it looks different depending on the programs.

Try opening the NEF file in Nikon View NX-i or Capture NX-i, both are available for free from Nikon. These programs read the settings used in the camera and will also give a yellow image to the image. Then use the white balance slider to get the right colors.