Chosen Solution
Got one in with multiple issues. Very dirty. Had viruses, bad HD/IR cable and failed drive, slightly swollen battery and mouse not tracking well.. Would not boot from power button. Opened it up and cleaned out. ended up replacing drive and HD/IR cable, battery, trackpad and cable. Trackpad kind of passably works but not down low. Replaced keyboard. Everything running great at top speed. Closed it up and found power button still not working. It boots when battery & mag-safe are disconnected and reconnected. Since I replaced the keyboard I was very surprised that it still does not power the machine up. Saw no evidence of liquid damage. Is there a logic board component I should look at and where is it?
You didn’t connect the keyboard flex properly; it’s tricky. Just make sure you pushed it all the way in and that it doesn’t move when you pull the tab down.
