Sorry to hear about your bad experience as a newcomer to SL EDET. Yes you can either sit down on a seat, or ground sit to be completely immovable. Also if you use firestorm viewer, you can press ctrl-alt-P to activate movelock, then nothing can move you from where you stand, you will however move very slightly but still stand on same spot. It can be quicker if you can't find a place to sit, or are trying to edit your outfit. http://wiki.phoenixviewer.com/move_lock. Also here is an old thread from this forum about the same issues that may hold some useful advice for you.