Unable to Log into wp-admin from my blog

My blog is at https://www.investmentcapitalist.com

Until a few days ago, logging into wp-admin worked fine. However, it just stopped working. I asked my hosting provider (hostgator) to troubleshoot and they said my admin.php file had been moved to another folder. Now when I type in https://www.investmentcapitalist.com/wp-admin I get a fatal error. After trying to troubleshoot with Host Gator, it now automatically reverts to my 404 error page. Please help.