|I have found a solution to this problem (with windows vista version, and 320 GB WD):|
click My Windows; double click 'My passport (H)' in the list of HD Drives; click 'File'; then click 'Close'. You will note that My Passport is either inactivated or disappeared by now.
You should be able to remove My Passport & WD Smartware safely by now.
In case this doesn't work, you may go back to 'My Computer' and do the same thing for 'CD Drive (F) WD Smartware in the list of 'Devices with Removable Storage'. That is, to double click (F);click 'File'; click (Close). You will also note that (F) is inactivated or disappeared. You are surely ready to remove WD Safely with these two 'closure' action.
Hope this suggestion is helpful to all users faced with similar problems.