Possibly bricked board?

So, being a novice at electronics I may have done something very stupid here.

I was trying to wire a new set of fans to my printrboard on my PrintrBot Simple.
Looking online I found someone had powered their second fan off of the heated bed pins, using one of the extension grounds.
I wired the fan up this way, and it worked. I had a second fan though, and wanted to route them both together. So at first I wired them in a chain, running the ground of one into the hot of the other, which had them both running very low power. I then thought I would instead just run the second fan off of a separate set of pins, so I disconnected power, and connected the second to the hot and ground pins of the E-Stop (assuming it should be always hot, and I'm not using it anyway). This didn't work, but I accidentally when rewiring it again connected the ground pin of the chained fans to the ground on the E-Stop (hot from heated bed into ground of E-Stop) which resulted in both fans running fine when I reconnected power.

Thinking it was a happy mistake, I went to re-connect to my PC to run repetier and noticed that I had left the USB connected the whole time I was re-wiring the pins.

I then disconnected everything and attempted to re-connect to the PC, but the PC did not detect that the Printrboard was being plugged in.
I tried disconnecting everything, adding a jumper on the bootloader pins and then powering up and then connecting and hitting reset.. no dice.

Is it possible that I've just bricked my entire board.. or is this possibly recoverable? Is it likely I fried the USB terminal somehow by leaving it connected or is it more likely I've done irreparable damage to the whole thing.

What set of safety precautions should I be using in the future when trying to mod my printer?
I do have the option to send this board back to printrbot for a replacement for $10, so thankfully not too expensive of a mistake, but I somehow doubt that this will be the last time I want to mod anything on any of my three printrboards and two of those were purchased from third parties.

Feeling really stupid, also sure this is a familiar tune to many of you.

First thing to do is to be very careful about what you take from various people's ideas.

The E-stop supply voltage comes from the +5V supply, not from the +12 supply. If you are on USB only, the power is coming from your computer. If you are on +12 only, the power comes from the +12 via a low power regulator. Your fan probably pulled more current than the regulator could handle. You may have smoked the regulator with the fan or by shorting the E-stop terminals.

If you want always on fans - wire them across the power supply. Forget about wiring them to pins on the control board. Only wire stuff to the board when you have to. Only wire things where they are intended to go. Hook up your power with at least #18 AWG wire if not larger.

Thanks for the advice. The Printrbot Simple only comes with a single 4 pin power-in. On my Delta I am building I have multiple other power connectors to pull power for fans from, but on the Simple there aren't any of those available. I suppose I could have spliced in a splitter to pull power from the 4-pin. Using the unused board pins for power just seemed "simpler" ha

I have sent in my board to Printrbot for a replacement. Probably will not get it for a week. In the meantime I will work on my Delta, though, it is a bit difficult to do much work on it without being able to print new parts.

One "easy" way to get the power split is to grab a terminal strip the next time you are at the hardware store. Splice one pair of leads into your power cable and run power to it via an automotive fuse block. Tie all the this and that off to the terminal strip.