1) Section 54 of TP Act defines sale as transfer of ownership in exchange for a price paid or promised, or part paid or part promised. If the value of the property is Rs. 100 and upwards, sale shall have to be effected only by a registered instrument.
2) in case seller had refused to register sale deed you ought to have filed suit for specific performance within period of 3 years .
3) admittedly for period of 23 years you have not taken any legal proceedings against the seller
4) you should approach the legal heirs for execution of sale deed for registration of the house in your name .