Apache2 error installing

I think the problem is not in the non-install ...

So the error says, it is already installed and at the time of the start it gives an error in the file /etc/apache2/sites-enabled/000-default.conf. The error description says that the tag is not closed (Open the file at a glance.) To close the <VirtualHost> tag use </VirtualHost>

Another thing, something nice to put next to the question is the version of linux that you are using and which is the specific distro and also shows us the way you are installing apache2.