 In February 1952 , Elizabeth II came to the throne and decided to make Windsor her principal weekend retreat . The private apartments which had not been properly occupied since the era of Queen Mary were renovated and further modernised , and the Queen , Prince Philip and their two children took up residence . By the early 1990s , however , there had been a marked deterioration in the quality of the Upper Ward , in particular the State Apartments . Generations of repairs and replacements had resulted in a " diminution of the richness with which they had first been decorated " , a " gradual attrition of the original vibrancy of effect , as each change repeated a more faded version of the last " . A programme of repair work to replace the heating and the wiring of the Upper Ward began in 1988 . Work was also undertaken to underpin the motte of the Round Tower after fresh subsidence was detected in 1988 , threatening the collapse of the tower . 
