"Unable to detect directx device" and Blue Screen...

[Regis_Obscurum]

[SIZE="5"]Unable to detect directx device[/SIZE]
Hello... I received today an original copy of Final Fantasy XIV, after the stupidly long registration process, I created my character and entered in the world, but when I pressed "Alt+Tab", the game displays a message saying "Unable to detect Directx device" and shutdown the game.

I have all drivers updated at the last version and also I have enough hardware specs for play the game in "at least" perfomance mode.

CPU AMD Athlon II x4 630
4GB RAM DDR2 800MHZ (OCZ Silver)
Hard disk drive 320GB
Windows 7 Ultimate 64 bit
Directx 11 version
nVidia GTS 450 1024MB GDDR5
Graphic drivers updated at last version

I looked in google for a fix, and I'm totally sure that this problem isn't related with the graphic card nor directx version, because this is the only game that provoke this error, also, as I saw, this error is old enough and haven't happened on the closed beta, sure that nVIDIA had enough time to fix this "uncompatibility" if was really their fault.

My request is, SQUARE-ENIX dev, fix this ASAP, because is RIDICULOUS play a game in window mode which does the view range smaller when the game have a 1080p display mode, we the players have expended money on Full-HD monitors for something, not for use them like an old monitor.

[SIZE="5"]Blue screen[/SIZE]
After played during 10 minuts in the world, my computer has crashed down, I configured the game as follows:

Window View - 1600x1024
Multisampling 2x
General Quality 5
Background Quality 3 (Standard)
Shadow Detail (Standard)
Enabled hardware mouse cursor
Texture Quality (Standard)
Texture Filtering (Standard)
-Other things untouched-
OCC DISABLED (never enabled)

I thought that maybe can be that my graphic card was overheated, but... I have two fans of 12cm in the side, 8cm fan on back and 12cm fan on front where are the hard disk drives, also the room temperature is less than 25ºC.

Has never happened with other PC games, so what thing can provoke the Blue Screen? I bought the computer on September 2010, so isn't too old for the game...