Completely removing phpMyAdmin

I was having a similar problem. PHP was working on my sites configured by virtualmin but not for phpmyadmin. PHPMyAdmin would not execute and the file was being downloaded by the browser. Everything I was reading was saying that libapache2-mod-php5 was not installed but I knew it was... so the thing to do was to purge it and reinstall.

sudo apt-get purge libapache2-mod-php5

sudo apt-get install libapache2-mod-php5

sudo apt-get purge phpmyadmin

sudo apt-get install phpmyadmin

sudo /etc/init.d/apache2 restart

If your system is using dpkg and apt (debian, ubuntu, etc), try running the following commands in that order (be careful with the sudo rm commands):

sudo apt-get -f install
sudo dpkg -P phpmyadmin  
sudo rm -vf /etc/apache2/conf.d/phpmyadmin.conf
sudo rm -vfR /usr/share/phpmyadmin
sudo service apache2 restart

I had to run the following command:

sudo apt-get autoremove phpmyadmin

Then I cleared my cache and it worked!