[TYPO3] HELP - Site has stopped working

[Sandy Matheson]

One of our Typo3 sites stopped working last night.

I can log into the BE with no problem

When you access the domain normally you get a file listing of the
contents of the root directory. When I click on index.php in this
listing I get a 404 error file not found.

Other Typo3 sites on the same server are still working fine.

It may be a coincidence, and I cannot see how it could affect this,
but the only thing I did last night was to delete a backup of the
files for this site.

I have checked the directory listing for the root directory and all
looks fine. The symlinks appear to be correct and all present.

The site is using Typo3 3.8.1

Any help much appreciated.

Many thanks,

Sandy Matheson