I agree with ronbo13. When you go for the free download, there are several versions. I recommend the one called Seatools for DOS. You install that on your existing C: drive, then use it to burn to your own floppy or CD-R disk a bootable diagnostic utility disk. You boot from that and it temporarily loads a mini-DOS into RAM with which you can run all the diagnostic tests completely independent of your Windows (or other) OS.