In a situation like this, I would always open the Task Manager (Ctrl+Shift+Esc) to see what the computer is doing. This lets you see if the internet is busy, it there’s a dialog waiting for your input, if your discs/CPU/GPU are overloaded etc.
There are many suggestions on the forum about how other people have solved similar problems, unfortumately due to various very different causes. It may just be a question of trying each in turn.