There r 2simple ways u may wanna try:-

1) go to my documents>diablo 3>D3prefs.txt. Open the txt file and edit "disabletrilinearfiltering" from "0" to "1".

2) delete the battle.net folder(hidden file) to clear the cache. The battle.net folder n contents will be re-created when u start the game client.

Above may worth a try if u still unable to fix per previous suggestions here. Both just take like 5mins effort. Good luck.