My Pfaff has locked up on me & can't pull the thread out of the bobbin area.Changed needle & bobbin thread but still won;t move. Any help appreciated.

I don't have your machine ... if it were my machine, I'd start by cleaning out the bobbin area. Could be a mass of lint in there!

Take off the face plate and see if there are threads caught.

Sometimes, if you use the hand wheel and just gently move up and down, it will let you pull out the thread.