RancidViper

You were right Steve, I replaced the halo.bmp with the original file and then re installed my rex textures and everything is back to normal. Well, on the ground that is. Turns out my Sun has gone all wonky.
 
Just so you know what I've been upto, I had installed nickn's sunfix to my fsx, and this was well after I had made the switch to DX10 and it was working fine upto now. Here is a screenshot. I'm not sure if this was related to the landing lights going wonky?
 

 
Previously I had noticed that my lens flare was not working correctly. I get the glare but not light refractions or whatever you call them. Now even after going back to the original sun effects, nothing has changed. Here is a screenshot of when the lens flare should be active. But it just shows the glare and nothing else.