Assassins Creed 2 Won't start.

[Leiaku]

Hello~

I brought Assassins Creed 2 the other day, installed it and ran the game.. but it doesn't work.
The launcher appears, and I click play in which then the launcher tells me the game is playing; but no game window appears.
I go onto my procceses list on Window's Task Manager in which it tells me Assassins Creed 2 is running but it's not appearing anywhere. Its not on the applications list of running programs and it doesn't appear anywhere on my screen etc.
I tried deleting my VisualBoyAdvanceEmulator thingy and for some reason that made the game work, but only once. The next day I tried to play the game and the same problem happened, so it seems deleting that thing either did nothing and it was a random chance it worked or it did something which has now gone back again. So yeah I'm really sad now ;_; Anyone know how to fix it? D':
I'll only post the beginning of DXDIAG thing but I'll post it all if needed. Just don't want to make this post too long ^^;
DXDIAG: ------------------
System Information
------------------
Time of this report: 8/23/2011, 21:21:38
Machine name: JOANNA-PC
Operating System: Windows Vista? Home Premium (6.0, Build 6002) Service Pack 2 (6002.vistasp2_gdr.110617-0336)
Language: =English (Regional Setting: English)
System Manufacturer: Dell Inc.
System Model: Inspiron 1545
BIOS: Phoenix ROM BIOS PLUS Version 1.10 A08
Processor: Pentium(R) Dual-Core CPU T4200 @ 2.00GHz (2 CPUs), ~2.0GHz
Memory: 3582MB RAM
Page File: 2137MB used, 5243MB available
Windows Dir: C:\Windows
DirectX Version: DirectX 11
DX Setup Parameters: Not found
DxDiag Version: 7.00.6002.18107 32bit Unicode
DxDiag Previously: Crashed in DirectInput (stage 1)

[GroundZero3]

What video card do you have? I looked up the model and noticed it only list the Intel® Graphics Media Accelerator X4500HD

Do you have the latest updates installed for the game?

[Leiaku]

ATI Mobility Radeon HD 4300 Series is my card
And yup I do.
It seems to be random when it works, sometimes it doesn't start but othertimes it does. O.o