When I try to start up the game, it'll show the initial updating screen and then the login. Once I type my details in, it seems to just do nothing. There's a "loading" box in the top corner and it stops there indefinitely. If I minimize the browser or tab switch and come back, it just becomes black.

 

I'm confident that I have the most recent versions of Catalyst and DirectX. RS runs perfectly fine in OpenGL and I'll probably just stick to that, but I'm curious as to why it doesn't work in DirectX.

There is known issues for direct X mode for thoose using ATI graphics cards, particular 5 series on the 2 most recent drivers; basically wait for new drivers and try again. Jagex and/or ATI will fix the issue at some point.

 

It is known that the 10.6 drivers work fine.

10.7 and 10.8 do not.

10.9 which came out yesterday theres no official word on, but judging by your experience its still not working.

Ah ok. At least I know now thanks.