Can't access my admin page

I’ve been setting up a new blog (I’ve done it 2 other times no problem). Something happened, either new plugin or something has caused my admin page to disappear as in it won’t open as it has before. Prior to this my widget page froze (that was yesterday). I need a back door to access the plugins so i can delete them without having to start over with this site. i tried /wp-content/plugins but no luck. Any other ideas.