Last try:

  1. Go to http://support.wdc.com/product/download.asp?modelno=WD1001FALS&x=15&y=11
  2. Click on the Data Lifeguard Diagnostic for DOS (CD) link
  3. On the next page, click on the Download button next to Diag504fCD.iso
  4. Once downloaded, burn the downloaded image using whatever suitable application, such as ImgBurn.
  5. Reboot your PC, boot from the CD, run the diagnostics.

If you can’t follow the above, then sorry but I really don’t have the patience nor the time to explain over and over again such simple instructions like how to click on a link on a website to download a file.