Move MalwareyBytes license from old hard drive.
This assumes your forgot to note the license info from the old drive.
1. Close MalwareBytes on new PC, Exit from tray
2. Copy from old drive to new drive
   C:\ProgramData\Malwarebytes\Malwarebytes Anti-Malware\Configuration\license.conf
3. Run MalwareBytes
It is now licensed. 
Write down your license info! Go to My Account in MalwareBytes.