Original Problem; some GIS files could not be accessed, because no qt5widgets.dll installed. I downloaded qt5widgets.dll from DLL-Files.com Client. This crashed QGIS program and I get:
The procedure entry point: ??0QAbstractTextDocumentLayoutPrivate@@QEAA@XZ could not be located in the dynamic link library Qt5Gui.dll. And Oops, looks like error loading QGIS. Details: Could not load qgis_app.dll. Windows Error: the specified procedure could not be found. Help: check C:\Program Files\QGIS 3.4\bin\qgis-g7.env for correct environmental paths.
I downloaded new qt5Gui.dll, but still same error, even with specific directions to download: Qt5Gui.dll Version 126.96.36.199. (Windows 7 64-bit) to \QGIS 3.4\apps\qt5\bin. Also uninstalled and reinstalled QGIS 3.4.3. No luck.
Is there anything I can do?