With Voldermort killed in the Battle of Hogwarts and scores of good wizards and witches annihilated in the last fight between the forces of good and evil, the magical population had declined in number to a great extent in Britain. But with the defeat of the "greatest dark lord in more than a century" by Harry Potter, the magical population realized they had a chance to once again rebuild their world. They knew it wouldn't be easy but with the darkness vanquished, they knew they had the time to do the hard work and make their world like it was before Voldermort had pretty much changed the whole fabric of the wizarding world.
Harry Potter found himself being asked by the majority of population to be the next Minister of Magic, something which made his best friends, Hermione Granger and Ron Weasley laugh at him since they knew how much he hated his fame and being in the public lime light. And it seemed that the more he tried to escape from it, the more it would follow him. But since he had flatly refused and quashed any such calls by the magical population, Kingsley Shacklebolt was made the next Minister of Magic, keeping in mind he had fought the Dark side long and his skill as an administrator even though he was a very skilled Auror.
Minerva McGonagall was made the Head Mistress of Hogwarts again after the last Head Master; Severus Snape had been killed by Voldermort. And even though the school had been greatly destroyed during the epic battle that had taken place there, repair works were carried out and the administration wanted the school to open from next September so that the world could return to normalcy as soon as possible. The Board of Governors and Ministry, both thought that opening the school as soon as possible would help the younger children to embrace the life before Voldermort changed everything for them in their lives.
The Ministry under Kingsley Shacklebolt, had repealed all the anti Muggle-born laws passed by the previous administration. All the people who had been involved with the dark side had been arrested and were being kept in captivity. It had been decided to check out all the suspected people by conducting a hearing in which Veritaserum would be administered to them and then their trial conducted. It was done to ensure the traitors like Malfoys and Zabinis, who had after the end of the first defeat of Voldermort pleaded they were influenced or not acting with the dark side, no excuse or defense and to finally get rid of the scum like that in the society. It was strictly ensured that the trials were fair and impartial to make sure only the guilty were punished, and all those who were found guilty were executed thereafter by making them go through the Veil of Death in the Department of Mysteries. This Ministry had decided to kill all the people with whom help the darkness had almost destroyed the wizarding world. The measures were completely supported by the general public who had suffered much at the hands of such people and wanted the traitors and double crossing people like Malfoys and other Death Eaters/supporters to be gotten rid of.
Amidst all this, Harry Potter found himself living in his godfather's old house now, Grimmauld Place. Kreacher still served him and had made the house now completely changed then from what it used to be. Now it was a cheery place and people weren't scared to move in the house fearing that some dark natured object would inhabit the house. He lived alone while his best friend, Ron Weasley lived with his parents now again in the Burrow, with his sister Ginny Weasley, brother George Weasley who had returned back there after Fred's death, and Percy had moved back as well. So the Burrow was now occupied by three of the Weasley offspring and Mr and Mrs Weasley themselves. Hermione Granger lived with her own parents who she had brought back from Australia where she had sent them to avoid them getting harmed by Voldermort when he was at the height of his powers.
The wizarding world slowly started to move forward from the Dark days of Voldermort. As a result to end the fear of Voldermort, the Ministry started to officially refer to him as MOLDY-SHORTS so the population could learn to laugh on him instead of still living in fear by his name even after he had been defeated. And this step helped the general public, which at first had been reluctant to address him by it, but slowly this name grew in popularity very quickly and Voldermort was Moldy-Shorts the dark lord. It amused the the magical world and also had the benefit of making sure that Voldermort, would be turning in his grave or in his case afterlife if he knew people referred him now as this.
With the Ministry, Hogwarts and the Diagon Alley going back to normal and the activity like the days gone past resuming there, the wizarding world started to move ahead of the dark days and create new memories for themselves.