The easiest answer is to change the password.  And don't save it this time!                   

                     Hmmm, that's surprising.  Let me see if I understand thsi correctly.

When you come to the Cafe, you are not automatically logged in right away.  But as soon as you go to log in, your username and password appear in the box and all you (or someone else) have to do is hit "enter" to be logged in.  Is that right?

That's something in the Windows operating system, not a part of the Cafe, so it's not something I know a lot about.  If it were me, here's what I'd try.  Enter gobbledygook for username and password, and when it asks to save that, say yes.  Then the next time you go back it won't know what to pre-populate the box with.

This might leave the gobbledygook username AND your username in a drop-down list, and your password is still vulnerable.  If so, select your username, then enter an INCORRECT password and save that.  Then, when you go to log in in the future, clear out the saved INCORRECT password and enter the correct one.

If none of that works, I'm out of ideas.

Good luck!