Plesk 7 & 8 Certificate Installation
Login to the Plesk 7 Control Panel.
From the left hand menu, select 'Domains'
Click on the domain name that the certificate is for
There is a button in the middle of the page labelled 'Browse'. Click 'Browse' and navigate to the location of the saved site certificate you received from Comodo. Selecting it, then select 'Send File', this will upload and install the certificate against the corresponding Private Key
The certificate name will now appear in the list of certificates at the bottom of the page
Click on the name of the Certificate from the list.
The box on the page labeled 'CA Certificate'. You will need to paste both the Intermediate CA certificate and Root certificates from the .zip file you have received into this box.
They must be pasted this in order, the Intermediate CA certificate first, followed by the Root certificate, the result will look similar to the
example below (Please note: no blank line between then end of one certificate and the start of the next):
Click the 'Send Text' button.
Now click 'Up Level' from the top right of the screen and choose 'Setup'
At the top of the page, change the 'SSL Certificate' drop-down menu to the certificate you have just installed.
NOTE: The example above shows a shared IP.
If there is no Certificate drop-down box on the screen, this means that you are on a shared hosting account, therefore you need to upgrade your hosting package and purchase a dedicated IP address from your hosting provider
Click the 'Server' item from the left hand menu
Click on the 'Service Management' menu item
You now need to Stop and Start the Apache process