diplomat ADP8322 bleeping/flashing?

hello , firstly i would like to say i have tried to read through all posts about similar problems but feel i still need a few more answers.

i've had my dishwasher 3 years now was installed with my new kitchen. the warrenty has run out and we didnt take up the extended insurance plan.

D/W was working fine until last week when after not using it for some days (ran out of tabs) i put it on a rinse cycle worked fine. i then loaded it up and off it went on it's normal 30/40 wash. it had almost finished when i heard the beeping at first i thought it was the end beeping but it just would'nt stop i turned it all off and put it on again but still beeping so i left it over night. started it again sunday morning but started bleeping straight away and flashing, i tried to select different programs but it just switches back on to the rinse cycle and bleeps again.
i came on here and my husband did what some posts said : took dishwasher out turned mains off, unscrewed bottom front panel (water all on the bottom) tilted back as much as we could , soaked up with towels, dryed up the bottom and all conections that could have got wet in the bottom,put plasters over cuts!, turned D/W back on BLEEP BLEEP BLEEP BLEEP

i have now put it back and left it till this morning when i thought it would have time to dry out . i have crossed my fingers and selected a wash, pressed button and no bleep just the sound of water filling up, opened door and yes the arms had started to move water was in the machine. closed door and listened in delite that it was working ........only to here BLEEP BLEEP BLEEP
i can not explain how gutted i was Sad .

so could any body please help me work the problem out we have checked for leaks (pipe to D/W & pipe to drain) no blockage or leaks there. have searched for how to reset machine pressing 4 times so on and so on (i know different model number but you never know)

do i call someone out and who?
how much could it cost?
can i do it myself?
or do i have to buy a new one?
do i have to reset it after?

please i'm a desprate housewife and it's half term