Not anymore Happy
*In 1917, there was a radical change, when George V specifically adopted Windsor, not only as the name of the 'House' or dynasty, but also as the surname of his family. The family name was changed as a result of anti-German feeling during the First World War, and the name Windsor was adopted after the Castle of the same name.
At a meeting of the Privy Council on 17 July 1917, George V declared that 'all descendants in the male line of Queen Victoria, who are subjects of these realms, other than female descendants who marry or who have married, shall bear the name of Windsor'.
The Royal Family name of Windsor was confirmed by The Queen after her accession in 1952. However, in 1960, The Queen and The Duke of Edinburgh decided that they would like their own direct descendants to be distinguished from the rest of the Royal Family (without changing the name of the Royal House), as Windsor is the surname used by all the male and unmarried female descendants of George V.
It was therefore declared in the Privy Council that The Queen's descendants, other than those with the style of Royal Highness and the title of Prince/Princess, or female descendants who marry, would carry the name of Mountbatten-Windsor*
From a quick Google.