Minimwatch won't run - java path?

[Glandwr]

Hi, after a disastrous experience with a Win 10 update which screwed up everything on my aging laptop, I had to roll back to a previous version of windows, but in the process of trying to get the new update working, I was asked to update my Java version, which I did. Now I've rolled back, all is running well except something to do with the java path (I think). I get the following when attempting to start minimwatch:

How do you want to open this file?
Keep using this app
"C:\Program Files (x86\Java\jre1.8.0_121\bin\javaw.exe" -jar "%1" %*


Now I know there is something wrong with my path as typing java in a cmd window gets no response, so I have attempted to fix the path but it got late last night and I don't believe I've set it correctly, so I'll start again with a clear head this evening.

My main question (finally!) is do I have to somehow change where minimwatch is looking for java as well? The path in the message is now wrong...