Need Monthly Giveaway deleted from website

Help? I want to delete a monthly giveaway that’s at the top of my website (which was created through wordpress by someone else), but I can’t for the life of me find out where to do it. I must have come across something, because now if you click on monthly giveaway, there’s a 404 error msg. I don’t want there to be anything for a client to click on as I have another promotion going on where they win free photos too. My website is https://pictureyourselfthinner.com