When I run it in command, it registers java as a legit command, but same thing. javaw.exe pops up in task manager as a process for half a second, then closes with no actual window.
If your a cmd window pops up, it might be because your default java program is the wrong one. CHnage the default to javaw.exe in your java installation folder.
I just updated to Minecraft 1.6.4 and I tried to reinstall forge, but when I double clicked the installer, nothing happens. I have tried a full java reinstall, including deleting registry files, and I have done the jar fix thing. I have both java 7 Update 40 for x32 and x64. When I do double click the .jar, a javaw.exe process pops up for half a second in the task manager. What do I do?