CSR was regenerated / does not match SSL Certificate

To install a SSL certificate, it must match the CSR generated through the Winhost Control Panel.  If the CSR is accidentally regenerated after placing a SSL certificate order, it will no longer be possible to install the certificate through the SSL Manager.  However, it is possible to rekey / reissue the certificate with the newly generated CSR.  Then install the reissued certificate through the SSL Manager in the Winhost Control Panel.
If a RapidSSL certificate was purchased, see the following article for instructions:  How to reissue a RapidSSL Certificate
If the SSL certificate was purchased through another certificate authority, generally a quick Google search for reissuing a SSL certificate through the applicable certificate authority will provide a link to the steps.
Alternatively, open a ticket with the Support Department, copy and paste the SSL certificate into the ticket and the CSR will be manually recovered and the SSL certificate installed.