OK, so I can't run jar files of any sort on my windows 7 pc, the one in particular I'm trying to use is the forge installer for minecraft so an installer window should open when i double click the file. I have Java and I set it to open with Java (TM) SE Binary but all that does is make the command prompt window open and then close again instantly. I have tried using the command method to open it but then it comes up with the error saying Error: Unable to access jarfile runable_jar.jar. I have downloaded the JDK file because I heard that was something I needed, but I'm not sure where to put it so it will do what it is supposed to. Was there something else I needed to download or is there something wrong with the version of Java I'm using. By the way I have a windows 7 64 bit if that helps.