ford focus 1.8 tddi eletrical fault 1999?

my focus has reasontly started to get eletrical problems. the window wipers struggle to move up and down the eletric windows struggle and other times they do not work at all, also the head lights blink on and off and when i break a buzzing sound happens in the glove box and under the bonnett oh and the engine runs with the keys out the ignition. a guy i no said my relays burned out but did not no why he replaced them with the fuse box but the lights still dnt work and the engine still runs when we turn it off. 2 weeks before the first prob i went through some deep puddles could tht be the prob? ive spent £100 and no further forward. do u think its going to be costy or worth fixing? paid £1600 for it. thankyou for your help. mike