Have you tried setting the time on the clock?
If not turn the power off and leave 30 seconds.
Then turn back on and press the - button to set the time and wait 5 seconds and this should allow you to use the oven.
Try that and see what happens but I also have the manual for this oven if you want it. Let me know and I can upload it for you.
Tried your suggestions but the buttons don't do anything, panel keeps on flashing and beeping
Ok if its not resetting then the only thing it can be is the clock as these are very prone to failing im afraid. Ive replaced loads of these on them ovens as they do fail a lot.
Click here for the part
This is a uk site but they will post parts out world wide so they will send the part out to you in crete.
As to fitting these are easy. You just pull the oven out and remove the top cover.
There you will see the timer. This is held in by 2 screws remove them then you can swap the timer over to the new one and refit it they are quite easy to do.
If you need anymore info just get back to me.
So even 'though there is power to the display panel, lights flashing etc it could mean a new timer? We get regular power cuts in Crete which always result in flashing panel lights but previously have always been able to reset
Yes im afraid when the timer is flashing its in auto mode so the oven doesn't work until a time is set on the clock and it stops flashing.
If you cannot reset it its because its faulty and as I said before these are very prone to failing like this. I have replaced load of them because it doesn't reset and set the time. You will need to replace the timer unit to cure this im afraid.