Sometimes you install a wordpress theme and activate You will get a blank page. No Admin No Front end the total wordpress gone to thin air. This is a great problem for me. Searched to reset the theme to default and get back the Admin Interface of wordpress. A simple Solution is here. NOT work everywhere. Before reinstalling the whole wordpress just try this.
UPDATE wp_options SET option_value = 'default' WHERE option_name = 'template';
UPDATE wp_options SET option_value = 'default' WHERE option_name = 'stylesheet';
It saved my life may time. You can also try this for resetting the wordpress theme to default and save from a wordpress crash of website. Happy Me …!!!