Where Did My Website Go??

A client called me and informed me that my website is down (AGAIN!). This time the screen is blank and nothing shows up. For all of the time that I have used Host1Free, I have never had any problems until recently. I am not sure what is going on, but this is my business website and I really need it to work properly.

Please advise. : Error 404 – Page Not Found

Thank You! Kelly