delete everything from this file: /usr/local/apache/conf.d/vhosts-ssl.conf
/etc/pki/tls/certs
delete your domain certificates files from here .crt,.cert,.bundle
/etc/pki/tls/private
delete your domain key file
Goto ssl generator fillin the entries and at the bottom also tick generate self signed certificate. Now generate ssl
Now this will generate csr, crt and key file.
Now you can goto ssl cert manager and on the right side you will see Install SSL Certificate.
in certificate, choose yourdomain.cert
for user, choose username of account
path, specify correct path
domain, name of domain
now click install ssl. This will enable ssl.
Open ur site with https and you will see error certificate means https is working.
on ssl cert manager page, scrool down and you will see option key, csr, cert,bundle, test. Replace content inside cert and bundle provided by comodo and restart apache (service httpd restart)