Layer Mask Blending Issue

[aya.x.papaya]

Alright, so this is really making me edgy and driving me insane. But about a week ago my layer masks in 7.0 stopped blending anything at all. I can still add it to a layer but when I drag the gradient to blend the images absolutely nothing happens. You can't even see that I used a gradient either. I've tried everything I can think of, or rather, everything I could remember clicking prior to that. I have even gone and uninstalled and then reinstalled the program in the hopes that it would fix the issue but suffice it to say that it has not.

If anybody has an idea as to why this is happening, I am willing to try anything as it is literally driving me mad.