nastav si spravne asociaciu.
Napr.
Step 1: Start Control panel
Step 2: Click Default Programs
Step 3: Click Associate a file type or protocol with a specific program
Step 4: Double click .jar
Step 5: Browse C:\Program Files\Java\jre7\bin\javaw.exe
Step 6: Click the button Open
Step 7: Click the button OK
http://stackoverflow.com/questions/8511063/how-to- run-jar-file-by-double-click-on-windows-7-64