How to run .jar file by double click on Windows 7 64-bit?

If you have previously used the right click and opened with \path\to\your\javaw.exe then you will need to remove the following registry key.

[-HKEY_CURRENT_USER\Software\Microsoft\Windows\CurrentVersion\Explorer\FileExts\.jar]

Then run

C:\>assoc .jar=jarfile
C:\>ftype jarfile="C:\path\to\your\javaw.exe" -jar "%1" %*

What is listed in right-click-> Open With ? Is some other program listed as the default program ? Is a Java Runtime listed ? If a Java Runtime is listed, you can open with it, and make it the default program to run with.

ie,

Right Click ->  Properties -> Change -> C:\Program Files\Java\jre7\bin\javaw.exe