Deactivating Theme

I have an issue with my password protected page. When I test it and submit the password it takes me to a 404 Error saying the page is missing. The URL shows up as wp-pass.php I have tried changing the permalinks and nothing works. It was suggested I try deactivating the theme. I am nervous I will lose all my content. Will this happen? If not, how do I actually deactivate and then reactivate the CatchEverest theme?