This happened to my Zanussi today!
Did what everyone above suggested - 
power off,
removed 2 screws at the back which secure the top, 
pushed the top backwards, 
unplugged the connectors to the front panel, 
all looked clean but I guess the vibrations due to unbalanced load may have loosened them,
pushed them firmly back in socket,
pushed the top (back to front, make sure a plastic tab seats properly to secure front part of top panel) in place and fastened the screws,
power on,
ran the machine empty for minimum cycle - rinse only.
Test ran OK.
Put a load into the machine.
Now, 70mins later, load is done!
Thanks to everyone for saving me a call to a sarcastic wachine machine repair guy!
                
 Shahryar
                
 August 2008