It might be because some configuration files are deleted, you have to reinstall it.

REINSTALL APACHE2:

To replace configuration files that have been deleted, without purging the package, you can do:

sudo apt-get -o DPkg::Options::="--force-confmiss" --reinstall install apache2 To fully remove the apache2 config files, you should:

sudo apt-get purge apache2 which will then let you reinstall it in the usual way with:

sudo apt-get install apache2 Purge is required to remove all the config files - if you delete the config files but only remove the package, then this is remembered & missing config files are not reinstalled by default.

Then REINSTALL PHP5:

apt-get purge libapache2-mod-php5 php5 && \ apt-get install libapache2-mod-php5 php5