Open Notepad and Copy and paste the following:
java -jar Launcher.jar
pause
"Save as" RSC.bat (or anything you want, as long as it has .bat suffix).
save to the same folder or directory where Launcher.jar is
Double click RSC.bat to open the launcher!
If that doesn't work, try using jarfix
https://johann.loefflmann.net/downloads/jarfix.exe