Cannot install stock heatsink on P43 board?

[j3ff86]

I just bought a Gigabyte P43 board and a E8400, but I can't install the stock heatsink's 4 pins even when I use a huge amount of force. I almost got opposite push pins to go but the board was bending in half. I followed the instructions and even watched a video on youtube and the guy used 0 force to push all 4 down. I noticed that the CPU sheath was a little bent, should it be like this? Should I return the mobo or just get a new heatsink fan from frys?

 

[msabo]

It needs to be installed in the case. The standoffs enable the pins to extend through the MB. Also push opposing corners at the same time.