No no, by Render method I mean choosing the options in the Options Box that appears. One of the options is the render method, OpenGL and another one (which has slipped my mind). Sometimes changing between the two can fix issues that are visual, which it sounds this might be.
I wouldn't think that downloading the other way would have any effect. You might be better to try downloading FH+ as well, and see if that has the same effect.
Another possibility is that your graphics card drivers arre outdated, you can get updates from their websites.