what you need to do is to add phpmyadmin to the apache configuration:
sudo nano /etc/apache2/apache2.conf
Add the phpmyadmin config to the file:
Include /etc/phpmyadmin/apache.conf
then restart apache:
sudo service apache2 restart
On windows, I think you can just navigate to the apache2 config file and include the phpmyadmin config file as shown above, then restart apache