Hello Atif,
The PAM matrix will provide information about which kernel is compatible with your release: link.
The easiest way to find your kernel download link is this route on the SMP: Support Packages & Patches -> Additional Components -> SAP Kernel -> SAP KERNEL 64-BIT UNICODE -> SAP KERNEL 7.21 64-BIT UNICODE -> Windows on x64 64bit
then select your DB type. And you will also need the DB independent part.
Best Regards,
Peter