angela

hi i have just purchased a lexus rx300, 2004 , having problems with sat nave, and also lexus built in video system . sat nav, screen just displays 'cannot read data, check map dvd', there is a dvd in not sure which numbers on it im supposed to read , but its version 2004\2005 version 1 ? mean anything to anyone.? it also reads 'no disc' when weve taken disc out, that mean its a disc problem ? not the actual sat nav? the dvd player is under drivers seat, and reads on the head rest screens 'no disc' when one is inserted. also one of the screens does not stay on ? any help?