i guess the previous owner found out it was a piece of crap too and sold the damn thing. go around n see him. 

u can chuck it or ask NEC/manufacturer directly on their tech support or cust info number why its so stuffed up.or ring a local NEC dealer, talk about it to them, and ask what they think it is, get a fixed quote before someone enters your house, and get your repair receipt/warranty on the repair in writing.
the good guys local electronics store will have the direct ph number for warranty repairs or at least the service hotline for the NEC stuff they sell..try that..they shld have a local good tech they use...

i have a piece of crap brand new dishwasher that has had no less than 5 techs out in 3 months, all under warranty. i told the last guy, if it farked up again, i was coming around his house...it hasnt played up since.