They use "security" screws to stop the owners messing around and electrocuting themselves - it's a safety thing.
The most common is Torx screw - you can buy little sets of security diriver bits quite cheaply from DIY & Tool stores & you will also need a driving handle. My Magimix Compact has Torx screws under the rubber feet.
I doubt very much if the switches have all broken at the same time - There's a constant run and a Pulse switch - if neither work then it's unlikely to be a switch problem.
Good luck...
Peccavi, September 2009
