MacBook not turning on after replacing trackpad cable
Listen buddy i have a similar problem. When you changed the ribbon cable you have probably forgot to remove the cable for the battery. This is why probably your battery went wrong. I also changed the ribbon cable myself and managed to unplugged my battery. This however did not fixed my keyboard and mouse issue (wish it did but it did not) but when i tried to turn it on it was just fine. I would suggest you unplug your battery leave it for few minutes check any cables around take off the ribbon cable put it back on. Then plug the battery properly put the protector on and try to start your mac. If that does not solve your second problem then you better start browsing for a new laptop.