johnnq1, stop and step back.
if u have to struggle with it, then most likely something is wrong.
either you got wrong screws, mount, or bracket.
It's supposed to be very easy to install.
I've two Ninja, one original plus and one rev-b plus.
The original plus has a cool looking (ninja kunai) metal backplate.
It has to be installed in place of the original AMD backplate.
On the top of the mobo, there's another bracket (plastic), screwed to that backplate.
After that, the heatsink just clips on it (4 clips)
The rev-b, has 3 mounts - 478, 939/AM2, and 775. Mounts go to respective factory backplates.
For 939, it only has 2 clips (939 style).
Good luck and don't use too much force!
Oh, almost forgot - best is to install it out side the case first. And after Heatsink is secured, then clip the fan, last!
You may have to adjust the fan position accordingly.