As of the moment, you're unable to install your QuickBooks Pro 2007 since it's one of the unsupported versions for QuickBooks Desktop.
In the meantime, I'd recommend contacting our Customer Care Support. This way, you'll be able to request a new validation code so you can register and install your QuickBooks Pro 2007.
Thus said, here's how you can contact our dedicated team:
As always, you can visit our Help Articles page for QuickBooks Online and Desktop if in case you need to learn some "How do I" steps.
Please let me know in the comment section down below if you have any other questions. I'll be keeping an eye for your response.