After completing your SSL activation and validation, extract the zip file that you received via email from Comodo or downloaded from your Namecheap account. Then upload the yourdomain.crt file (Security Certificate) to the same folder where your CSR code was generated.
Now return to the command console and run the following command:
certreq -accept example.com.crt
NOTE: Depending on the server type you selected during SSL activation, you may receive an SSL certificate file from Comodo with .crt or .cer extension. If you downloaded this from Namecheap, you will have PEM- and PKCS#7-formatted SSL certificates with .crt and .p7b extensions. Regardless of how you received your certificate file, the aforementioned command should still accept it - just make sure that you write the correct file name.
Congrats! You’ve just imported your SSL to the Windows certificate storage. The certificate can now be used by other Windows services like IIS, Exchange, Active Directory, etc.
Feel free to check the SSL installation using this tool.