So I'm running along and all of a sudden my screen wigs out. I can't really describe it... it was kinda like the terrain started to invert itself. not just upside down but weird... and color was off as well... w/e... so i log to player select screen... then back in... still the same.... so then I log all the way out and then back in..... same... so I restart... come back idk like an hr later.... still the same... this is on my win xp workstation has played fine since release etc. So I go upstairs to my win7 laptop thinking it has to be something wrong with THAT machine.... same thing... so I run my pathetic behind to a completely different zone... mind you I can't see anything in terms of direction just a discolored series of mountains while character is just sort of running in place.... I finally get to the marker on the minimap and then as i get further and further past the marker rather than seeing a tranquil green forest I see nothing but what little resemblance of a background environment I had dissolve into what looked to be little more than a dust storm and even that is a stretch of the imagination... no my friends I'm not making this up... and I figured since I'm pathetic enough to use the minimap to run ALLLLLL the way to the last known working zone I figured I may as well spend the time to document this small but meaningful moment of my life.
Artifacts like that are usually graphics card issues.
Whether Driver related, DirectX related, or Hardware related, it's a graphics card issue of -some- kind.
It's near impossible to diagnose too, but you may find better luck going to something like the Nvidia or ATI forums and asking there.
I know I had some issues like this in Everquest II and I couldn't figure out why it was only in that game, but I eventually found out that it was because EQ2 was using a certain type of rendering method most games had abandoned so I never noticed the problem in other games. The problem was a faulty shader on my card but eventual driver updates seemed to make it go away.
Anyways try updating your drivers to the newest version.