To my question:

In the process of reapplying the TIM on the CPU/GPU heatsink, I failed to remove the protective bracket over the trackpad/keyboard wire on the logic board. As a result, the trackpad wire is ripped up pretty bad. The keyboard wire seems all fine but did get snapped out by force from its connector, during the incident.

When I powered on the mac (not really understanding at first what had happened, yeah I know, just shoot me) the mac reported that it did not have a trackpad connected. "No problem, we'll use the bluetooth magic mouse, which works." Well then the keyboard doesn't work. "No problem, we'll use the spare USB keyboard". So when I've managed to both point the cursor to the password window and write it down, the mac says "Login is not possible because an error has occured."?

I'm really lost. I've managed to buy a spare trackpad cable, which will arrive mon-wed 8-11.4, but what is going on with my keyboard? And the login?

As a final shocker twist in this plot, the keyboard does work(power on, keep option in, arrow keys to navigate partitions, enter to choose), when I boot into the bootcamp W7 partition. Which then obviously proceeds with never loading but stopping at a black screen.

As I said, I'm lost. Is the trackpad cable a good place to start? I sure hope so. What else is going on with my mac? Will I need a new top case? Is my OSX broken?

This I know - a dude fixed his trackpad and keyboard by just repositioning his trackpad cable, on a 2008 MBP:

link to Apple communities discussion thread.

Thanks all

EDIT SOLUTION FOUND FINAL FIX

I bought a replacement trackpad wire quite cheaply via ebay and following the guide found here on ifixit installed it. Surprisingly for me the rumours and claims found when googling around is true - the trackpad wire does have something to do with the keyboard and topcase aswell.

A bit sadly disappointed for not getting even one trial answer from anybody here, oh well problem solved and I will continue onwards.

Good luck to anyone who might stumble onto this little monologue of mine - DO NOT BUY A NEW EXPENSIVE TOPCASE JUST BECAUSE SOME SELLER SAYS SO - this happened to me and luckily my trackpad wire arrived so swiflty that I didn't have even time to order that US$300 replacement topcase.

⟐ Answered April 10, 2013 at 1:28 pm -0700