Short answers, pulled from the story.
Maria Theresa ascended to the throne on the 20th of October 1740 following the death of Holy Roman Emperor Charles VI in Vienna. She was twenty-three years old when she inherited a treasury containing only 100,000 florins and an army reduced to about 108,000 men.
Frederick II of Prussia invaded Silesia within days of her father's death starting an eight-year conflict known as the War of the Austrian Succession. The Treaty of Hubertusburg and Paris concluded the conflict in 1763 confirming that Silesia remained under Prussian control despite years of fighting.
Friedrich Wilhelm von Haugwitz modernized the empire by creating a standing army of 108,000 men paid for with 14 million florins extracted from crown lands. He instituted taxation of the nobility who had never before been required to pay taxes establishing central government responsibility for funding the military.
Maria Theresa proposed expelling approximately 10,000 Jews from Prague amid accusations of disloyalty during the Bavarian-French occupation. The order was expanded to all Jews of Bohemia and major cities of Moravia but retracted only in 1748 due to economic pressures from countries including Great Britain.
Emperor Francis died on the 18th of August 1765 while celebrating his second surviving son Leopold's wedding in Innsbruck leaving Maria Theresa devastated. She declared Joseph her new co-ruler on the 17th of September 1765 initiating frequent ideological disagreements between mother and son.