You could test the batt in another bike, right? You could also test shifters, etc but depends how much spare cable you have or if you have cable extender.
I believe there is a password on the bios too.
Without going into too much detail, it's an inherited ex corporate machine, I can log in and use it but can't make any changes/install anything
No disc drive. I actually do remember using floppies as a kid. Not a euph. I'm not that young!
Anyway I tried a new junction A, no fucking difference so it's a wire or junction B I guess