A Bug About the Login screen on the alpha client

So my screen does not fit the login screen to login in so I tried to move it. In doing so the login part with all the spaces where u put all your information to login disappeared. And I can't x out the login screen because there is no button there. So I had to task manager and end task the login screen. After doing that I tried to open the alpha client again but it won't pop up even after I waited for 30 minutes. I am hoping u can fix this because I have to uninstall then reinstall the alpha client.