Now I can plug the mobo into the case just fine, but when I try and put the GPU in, it simply does't fit. It doesn't line up. It's too big.
Can somebody with more knowledge than me tell me if this should work or not. If it should then I'll just try harder, but if I know it shouldn't then I'll need to find a different solution.
EDIT (more detail): When I put the GPU into the mobo, the part where it should be screwed into hits the case before the GPU is properly plugged into the mobo.