If none of these work, you are likely dealing with a corrupted SQL instance or a Windows OS conflict. In that case, the "best" ultimate solution is a (the officially recommended OS for WinCC 7.5) followed by a fresh WinCC installation.
: Try running the reset script located on your desktop or in the WinCC installation folder. This often clears stuck background processes that prevent a fresh application start. a basic application could not be started wincc 75 best
