You either live with it or pay the $29.95 (I think) fee, they then send you the key which disables "tips". If you decide to live with it, Powerstrip also randamly "loses" user settings.
...in which case it's a good idea to copy your custom setting to the clipboard (there's a button), and save it to a text file, so it can be imported again.
Someone here said that if you uninstall Powerstrip the resolution is kept in the registry - I tried it and it seemed to be at first, but then it disappeared.