Unresponsive programme switch DIPLOMAT ADP 8234?

Please advise, my Machine displayed PO 19 and would not let me use any of the programmes.
I read t hat if the programme switch was depressed 4 times it would allow a reset, this i did but instead of reset i got a flasing light saying c3 i closed the machine and it partially washed the load and then returned to the PO message this time it was PO 25 the 4 push reset is unresponsive and the message has now gone to PO23 im at a loss and could do with some sound advise. would appreciate some help regards Bud