Replaced battery, now no keyboard or trackpad

I performed the battery replacement procedure. When booting up afterwards, the fans both run at full speed, the computer seems sluggish, and the trackpad and keyboard are unresponsive. Power button works fine though.

A window pops up stating there is no keyboard connected. I’ve been able to connect my Magic Mouse, but no luck with a Bluetooth keyboard, so I’m unable to access the OS, or perform the often suggested SMC reset.

I did reopen the case this morning and double check all the connections and screws and everything appears to be in order.