White screen after login

Suddenly if I try to Login box from Login on home screen, it automatically goes to a white blank screen. If I type in login.php after my website name I get to WP login. I then enter username and PW and it goes to a blank white screen. If I go up to nav line and type in admin.php after my website I can get to my website showing the WP menu bar at the top. If drop the submenu bar to select Dashboard, it goes to a white screen. I tried typing in wp-admin/index.php after website name and it goes to a white screen. How can I get back into my dashboard????