Bought minecraft and it won't work, what's the problem?

I bought minecraft and it won't play. I open the launcher and after i press the play button the green bar takes its time loading and then nothing happens. I press play again and again and nothing happens. I tried deleting everything in the.minecraft folder and re-downloading and non of that works.
please help me

Added (1). my computer specs are high enough. I checked through can you run it

Check if your username and password are correct, thats what might be stopping it