Hello. I've been working on this for a couple of days now and nothing is helping. Here's a recap of my process so far:
1. Java Uninstaller. Uninstalled all versions of Java with the uninstaller on the site to be sure they were gone.
2. Reinstalled Java. No dice. The cursor changing for a moment is all the response I get.
3. Jarfix. No dice. Same as 2.
3. Java JDK. No dice. Same as 2.
Now, to be clear here, the file associate IS CORRECT. I've checked this in the Default Apps section of my settings and the icon for the Forge installer IS a Java icon. Association does not seem to be the issue. I've been looking around the forums here for help for the last 3 and a half hours and managed to find that some people have tried starting the thing in cmd. When I did that, I got this error: "no main manifest attribute, in forge-1.15.2-31.2.0-universal.jar" . If you are not a coder - like me, soooo not a coder here! - don't Google that. It will break your brain if you try to read some of the more technical posts on that... you've been warned. Anyway. I have no idea where to go from here. Any help is appreciated. Thanks! ♥
EDIT to add: I should say that I used the Jarfix ini file to try to use both of the Java versions I have - from the JDK and the JRE. I did this AGAIN after I found out about the cmd trick and got the same answer with both files attempting to run the jar.
Just realized I've been using the wrong version this entire time, my apologies. I am so, so sorry, I could have sworn I deleted the thing. >,< The regular installer still won't run normally, but I got it to open with the cmd prompt.