DATA CORRUPTION PROBLEM SOLVING
First you run "Files" -> "Utilities" -> Rebuild to try and fix a data problem. If that doesn't work, send your data file into Intuit for a few days to see if they can repair it. Intuit charges for this service, except they waive fees for Enterprise users, Pro Advisors, etc. If Intuit can't fix your database, your remaining option is to create a new database, i.e. company file.
CREATING A NEW DATABASE
It's easy to get lists from your existing database to the new shell, but it's harder to get transactions. My way is to purchase 3rd party add-on software, QB Data Transfer Utility to move transactions from one data file to another. The software wants all the relations between lists intact, so move data first, clean up lists afterwards. The ability to clean up lists, and start payroll new are other compelling reasons to create a new database, or at least a silver lining.
Ideally you'll create a new company file for Jan, so that you can start off the year with clean data entry. In that case, I can use QB Data Transfer Utility to transfer open invoices, unpaid bills, and uncleared checks. And then you can start fresh with all your other transactions! Whatever your needs, I will do whatever I can to help your business run smoothly.