Unfortunately, neither way will yield any results. You have a 16 character serial with 36 character charset, that is 36^16 combinations, almost 8*10^24.
Assuming you crack trillions of passwords per second, it will take thousands of years to go through all these combinations.
If you still want to try cracking the hashes, then use a tool called
hashcat, making a program yourself will most likely be very slow compared to it.