First off, you need to see what kind of error message the crash / disappearance is producing. To do that...
1. Open a Cmd window.
2. CD to your SQL Developer installation's sqldeveloper\sqldeveloper\bin directory.
3. Run .\sqldeveloper.exe
You should see some messages. The two most common scenarios:
1) If the Java Virtual Machine is crashing, it could be Java not interacting well with your machine's video driver version. Try updating it.
2) Corrupt user settings (for 19.1, C:\Users\<yourID>\AppData\Roaming\SQL Developer\system19.1.0.094.2042). Delete the dir and try again.
If it is the lack of a msvcr100.dll on your PATH, or some old, incorrect version, put a copy of the one from the bundled JDK in a directory included first in your PATH variable.
You made me happy again!
The Drivers were all up to date, but the second step was the winner!
I really thank you!
have a good evening!