Adafruit motor shield - Motor rotating only in one direction

So, I got this Adafruit motor shield to run three motors. I am not using it as a shield, but taking jumpers out of the board to connect to the arduino (I have a mega). I am connecting pin 3, 4, 5, 6, 7, 8, 11 and 12 in the shield to the mega and the gnd of the shield to the gnd of the mega (These are the ones that the manual said were involved in the operation of the motor). I then downloaded the library and installed it as per instructions. Now, the problem is that it is only rotating in one direction. I am not able to figure out why. I even tried using jumpers and connecting all the other pins which would have been connected if I used it as a shield. Connecting the 5V to 5V actually made the motor non-functional. Any clues on how to solve this would be much appreciated and also, if anyone can shed light on the 5V issue I mentioned, it would be great too!

Thanks. Cheers, Ab!

What does your code look like? Post a picture of your connections, too.

Why are you not using the shield as a shield?