You have successfully downloaded the OpenRocket file; however, it appears that your computer has been configured to automatically open ".jar" files with a program called WinRar which is not what you want for the OpenRocket jar file.
WinRar is a program that allows you to compress files and view the contents of compressed files (archives); it is very similar to a program called WinZip which does the same for ".zip" files.
It appears that WinRar is installed on your computer and it has been associated with several file suffixes, including ".jar".
On my Windows 7 system I have created the following shortcut to point to the OpenRocket jar file that I downloaded:
Code:
"C:\Program Files (x86)\Java\jre7\bin\java.exe" -jar "G:\Rocketry\OpenRocket-13.11.2.jar"
Please be aware that this shortcut references the location where I have my Java JRE installed and the location where I have my OpenRocket jar file located on my computer and this is probably different from where you have your Java and your OpenRocket.
Finally, you might want to consider changing which file suffixes are associated with WinRar. For instance, you might want to navigate to the place where you have the OpenRocket jar file and right-click on it and choose the "Open with..." option to let Windows know what program should open this file suffix by default.
Good luck,
Cor
