This probably means the thermostat has tripped. It's a common fault with these tumble dryers - ours has failed on at least 4 occasions now. I've discovered that it may be possible to fix it by resetting the thermostat:
Unplug the machine!
Remove the heater assembly (rear of the machine - two screws to remove the spindle cover then another half dozen screws and the heater assembly comes away).
Take out the heater - two screws hold it in.
At the top are two thermostats - a white one and a black one. The black one has a small hole in it and can be reset by pushing a pin into the hole until a 'click' noise is heard.
Reassemble, plug back in and test.
Note that even if this fixes the problem the unit will probably show F10 a few weeks later; I think it's just the way these machines are - a design fault.
If the above doesn't solve the problem then it may be worth buying replacement thermostats - a kit will include both the black and the white one and cost around £25.
James
September 2006