Need Help - KMTTG JAR File Does Not Execute After Clean Install of W7

Hi, my great custom desktop pc of 6 years died and I had to get a new one, but the W7 Prof install on my SSD of course would not be recognized and I had to install a new fresh copy. All W updates have been applied and Java has been installed. When I click on the JAR file, a blank black window comes up and then disappears, the program never starts. I been in IT for many years and I have researched this problem for quite a while now. It used to work on my previous W7P install (from same dvd) and it also worked on my laptop on W7 Home and also still works on the upgraded W10 Home on there now with no problems. I have the JAR file associated with JAVA.exe just like my laptop.

Does anyone know what possibly can be wrong? I have looked and looked. I would greatly appreciate it if someone could help...:D

THANKS