usb boot hard reset to clean install osX?

First I doubt you got a chipset virus! While there was some research into creating them they just didn’t work in the real world. More so within OS-X or MacOS as Apples firmware is very different to Windows systems and even now is not a large enough population of systems for someone to bother with.

So let’s focus n the more likely issues here… given the systems age I’m thinking the battery has swollen up pressing from below. But before we get into that, let’s see if we can get into the system using an external USB keyboard and mouse, plug them in and see if they work (ideally an Apple keyboard and mouse) see if you can borrow one from some one for a few days.

If that works that proves the issue is likely the battery. Here’s the needed part MacBook Pro 13" Retina (Early 2015) Battery And guide MacBook Pro 13" Retina Display Early 2015 Battery Replacement you may need to replace the MacBook Pro 13" Retina (Early 2015) Trackpad Cable as well as often it gets damaged. In fact I just walked someone through installing a new one here MacBook Pro 13" - Keyboard and trackpad working intermittently review what I wrote on how to install the new cable.