I want to copy the C: drive on our desktop to My Passport

WD External Drives WD Portable Drives
2

Try FBackup 4 - a freeware program.  It will allows you to make an image or clone the drive.

If you just want to copy some files, try “Gyula’s Navigaor” - another freeware program. Great program but don’t accidentally delete something important.

Google for these 2 programs.