Thanks for the in-depth details of the troubleshooting you've done to fix it, KSCB.
It's possible the Loan Manager (.lmr) files are missing when moving the company file into your new computer. Aside from creating a backup copy and restoring the file, let's try using the Migrator Tool. This way, the tool will download the correct version of QuickBooks to your new computer and sets it up with your files.
Just follow the steps and details in this article: Move or reinstall QuickBooks Desktop to another computer. Then, go to How to set up and use the Migrator Tool section.
You can also check out this article for other troubleshooting options: Loan Manager or Cash Flow Projector is missing after upgrading QuickBooks Desktop.
To learn more about how the loan manager works in the software, just refer to the QuickBooks Loan Manager article.
Keep me posted by leaving a comment below if you need a hand with migrating data into QuickBooks. I'll be here to help.