You've just come home from a long trip or decide to put a stored computer back in service. Give it more time to get re-acquainted. First, don't start panicking if Windows doesn't immediately appear. It might take up to 15 minutes. After that you can start using repair options if needed. After Windows is operating:WAIT. Your machine has a lot of catching up to do. Apps are reviving and Windows itself needs updating. If you start expecting immediate performance, to put it simply, you'll give your computer brain overload. As in all things, practice moderation.