re-install the certifcate

I am an Comodo affiliate, my client has removed the certificate from his windows server 2008, and he didn’t export it also (as a backup), but he does have the original certificate from Comodo,
when he made import certificate form the sell command line, gave him an error that the Private Key doesn’t exist,
I told him that he should make a new request to generate the CSR and then import the certificate.
he also did it, but it gave him another error that the private key doesn’t match

Do you have an idea how can we get the certificate work again?

Have your client submit a ticket off of https://support.comodo.com with a brand new CSR and we’ll get the certificate re-issued.