Hi Sri sai Nivas,
I am Dave, I will help you with this.
This is a terrible situation caused by the motherboard change, if you are unable to find the Bitlocker recovery key on either of those accounts, then honestly, there is no way to access that drive, the encryption is too strong, the only option will be to clean install Windows on the laptop from a bootable USB, and the drive will need to be wiped to remove Bitlocker, and that will result in loss of all data on the drive.