default.html

I've accidentally deleted the default.html file. Does this affect my site? I can't load my main page correctly. However, if I put in the index.html after my url, then my page can load correctly. I suspect this has got something to do with the deleted default file. I tried to locate but can't. Can someone point me to where I can undelete the default file or a work around this problem? Thanks very much

Lydia