Hi Mike,
When you go to My Home, click on Edit next to "Personal info....", and change your password, are you clicking Submit at the bottom of that page?
If so, and when you do this at work, can you log out and in again with that password (at work)?
If that works, something is amiss at home. Try typing your password into an a regular editor and see if there is a keyboard issue.
Either way, let me know, OK?
btw. expiring the cookie shold not affect your password....
