I appreciate you sharing the complete details of your concern, @Apeface. I’m here to offer my assistance to keep your account from crashing/freezing up.

Before anything else, this certainly isn't the experience I want you to have, but I need to ensure I have the exact information on the issue. Can you share what error message you received? Additional details would be much appreciated, such as screenshots. To help me isolate the issue, and provide the best solution.

In the meantime, let's make sure that you have updated QuickBooks Desktop to the latest release to keep your software up-to-date so you always have the latest features and fixes. After that, let's open your company file with a different QBDT user. 

Here's how:

1. Go to the Company menu at the top.
2. Select Set Up Users and Passwords and click Set Up Users.
3. Click Add User, type the username and password, and click Next. Please don't use the damaged user name.
4. Customize the user as necessary and click Finish.
5. Go to the File menu and select Close Company/Logoff.
6. Log in to the company file using the new login credential.

If the new user doesn't resolve the issue, let's create a new Windows admin. If you're using Windows 10 and newer, here's how:

1. Click Start.
2. Select Settings, then click Account.
3. Choose Family & other users.
4. Select Add someone else to this PC under Other Users.
5. Select I don't have this person's sign-in information, then select Add a user without a Microsoft account.
6. Enter the name of the new account.
7. Click Finish. You may also assign a password to the new account to ensure security.
8. Choose the newly created account and select Account Type.
9. Select Administrator and click OK.

For more information on the steps above, see this article: Troubleshoot Unrecoverable Error XXXXX XXXXX. 

Then, refer to the following article for the troubleshooting steps for the specific error you've received: Unrecoverable Error: General Troubleshooting Steps. 

I'd appreciate it if you'll update us about the troubleshooting process. We want to make sure you can work on your business again.