skype not remembering password in another PC?

Hi,
I've been using skypeportable for years, several versions, mainly 5.x.
One thing I don't like is that the password part is not indeed portable --- if running in another PC, or current PC has an OS reinstallation, I'll be asked password. And you know, we're easily forgetting password in a long run.
Does everybody has this problem? Where/which file is the password saved?
Any idea?