Magento site keeps going down and only showing blue text...hosted thru host gator

Hi
Our new site went live two months ago. Now all of the sudden it's crashing...hostagator couldn't get it back up at all....my developer did and said that files had been changed to bak... That was fixed but it's doing it again. No one has been on it or messed with it? Is there something in magento that would make it do this?
My website is www.shoppetal. Com
Thanks!
Jammie

U need to check if you have installed the latest security patches. After that you need to change all the logins to Magento admin panel, to MySQL and access to the hosting. If your site was hacking up, smbd stoll this info.