How will you use this once you have the threaded hole in the block? Is this for looks or for 3D printing? Assuming the latter, one approach would be to let Solid Inspector fix what it can and repair the rest of it manually so the screw is a solid component. Then make the block a solid component before subtracting the screw from the block.
Alternatively, you could explode the screw component, use Intersect Faces to make any needed intersections at the top face of the block, and then erase the bits of the screw that protrude from the block.
Due to the very small size of the screw, you’ll want to use Dave Method for either of these processes. If you choose to use Subtract, use the one in Eneroth Solid Tools or Bool Tools2 so that the block doesn’t get converted into a group.
Also assuming this is for 3D printing, it’s worth considering that the screw component is pretty rough and won’t yield very nice threads in the material. Also consider that normally the female threads are not an exact duplicate of the male threads. I’d be inclined to just draw a smaller hole in the block and tap it after the printing is complete.