The Balance Sheet, check register, and writing check window should always have the same ending balance, Rachel. FishingForAnswers is correct. It could be that you accidentally select another checking account instead of choosing the appropriate one. 

I appreciate you for reviewing the name of your checking account and ensure you pick the right account on your Write Checks window. 

Since you're getting the same result, I recommend you manually update your QuickBooks Desktop to the latest release. Then, run a rebuild data to fix this odd behavior and other issues in your company file.

1. Go to the File menu.
2. Select Utilities.
3. Click Verify Data then select OK to close all windows.
4. Then, go back to the File menu.
5. Select Rebuild Data under Utilities.
6. QuickBooks will ask to make a backup before rebuilding your company file, select OK.
7. Once the rebuild is done, click OK.
   

    

Here's an article for further guidance: Verify and Rebuild Data in QuickBooks Desktop.

Let us know if you have more questions about viewing the correct balance and other data in QuickBooks Desktop. We're all right here to help in any way that we can.