Encrypted my passport 500 needs no password?

When I connect my “my passport essential”  500 gb to my xp professional laptop, the unlock screen comes up and if I just click the unlock tab, without entering a password the drive unlocks?   the drive is set to be encrypted and when I use it on any other machine I have to enter a password to unlock it.  But not on my own laptop.  even rebooted and it still did not need a password.  Tried connecting and disconnecting a few times and still did not need to enter password to unlock and access files.  As I keep other peoples health info on this hard drive it must be encrypted.

Any suggestions

best

broomast

Depending on the Passport model that you have, try uninstalling/reinstalling Smartware or WD security and check if that helps. 

http://support.wdc.com/product/download.asp?groupid=218&sid=172&lang=en