Switch the machine off with the 'Mains On/Off' button, then press first the 'Temperature' button whilst switching the machine back on, then the 'Soil type' button within 6 seconds, one at a time, not both together. If you are not quick enough you will have to switch off and start again. a diagnostic screen should then come up telling you a code number for the fault. now you can switch the machine off, then on again, and it should have now re-set an be working (unless the fault is a serious one). let me know if this works for your fault, as it does for many of them.
TAKEN FROM ELSEWHERE ON THIS SITE
STEEV, December 2004