Anti-Aliasing not working on ANY game

Hi guys

At first I thought this problem was isolated to the game ARMA III. However, I’ve noticed that all my games have been affected by this issue. It looks like my anti aliasing has just broke! And I get many screen tears even when Vsync is enabled.

Here are some examples:
http://cloud-4.steampowered.com/ugc/64495616120691916/212FCABDEEA4FBD25DDBFBB58577E60712E4CC8E/

http://cloud-4.steampowered.com/ugc/67872681817313348/11FF7241A8E496E84D9DF2C2CDEE3E2CB2544A3D/

Can you guys please help :(