Hello there, VickiL.

We can change your Windows DPI and screen resolution while the option to enlarge the font is unavailable within QuickBooks. Changing the settings can also affect other programs or apps in your computer.

Moreover, I got four solutions for you on how to fix the issue. 

Solution 1: Change QuickBooks DPI settings

1. Right-click on the QuickBooks icon, then select Properties. 
2. Click the Compatibility tab, and select Disable display scaling on high DPI settings.
3. Click Apply, then OK. 
4. Open QuickBooks and check to see if the windows are visible. 

Solution 2: Change the Desktop View Preference

1. Open your company file.
2. From the Edit menu, select Preferences > Desktop View > My Preferences.
3. Switch View from Multiple Windows to One Window.

If these solutions don't work, you can check out solutions 3 and 4 in this article for more details: QuickBooks Desktop display issues. 

If you have further questions, you can always go back to this thread.