this seems to be a hardware problem. your graphics card is way outdated and it would probably be a good idea to upgrade. generally your screen will go black like that usually due to your Graphics card overheating. also you're running vista which uses waaayyyy too much processor power to run and is probably adding to the problem. i would upgrade my Operating system and Graphics card. i got a Nvidia GT 630 a few months back for around 80 dollars and it runs FF14 nicely, i'm also running windows 7 - i'd recommend getting that.