Hello Emma,
If you can't lift up the presser foot on your machine the chances are that you have far too much pressure on the foot, if you have a dial on top of the machine turn it down to about number 3 and check, if you have the chrome thumb screw type just unscrew it until you lift the foot easily, if that does not work let me klnow or leave another question.
Ken
drivewithken@blueyonder.co.uk, July 2007