Vista - Display freeze and black screen

Hi Gentlemen,

I am trying to understand what could trigger display freeze and black screen
on my HP laptop running Vista Ultimate.
The occurence as follows : In such situation, the screen display freezes
and the CPU hangs . One cannot move the mouse, and even typing CTRL+ALT+DEL
produces no response, the system remains in this state unless one holds down
the power button to restart the system. I would like to know if
compatibility problems exist between Vista with DirectX 10 and a Graphic
card device driver based on DirectX 9Ex ?
Some data from my system that may help :
System Information
Operating System: Windows VistaT Ultimate (6.0, Build 6000)
(6000.vista_gdr.071009-1548)
Language: French (Regional Setting: French)
System Manufacturer: Hewlett-Packard
System Model: HP Compaq nw9440 (EY612ET#ABF)
BIOS: KBC Version 54.3B
Processor: Intel(R) Core(TM)2 CPU - T7400 @ 2.16GHz (2 CPUs), ~2.2GHz
Memory: 3454MB RAM
Page File: 1011MB used, 6070MB available
Windows Dir: C:\Windows
DirectX Version: DirectX 10
DX Setup Parameters: Not found
DxDiag Version: 6.00.6000.16386 32bit Unicode

Display Devices
Card name: NVIDIA Quadro FX 1500M (Microsoft Corporation - WDDM)
Manufacturer: NVIDIA
Chip type: Quadro FX 1500M
DAC type: Integrated RAMDAC
Device Key: Enum\PCI\VEN_10DE&DEV_029B&SUBSYS_309F103C&REV_A1
Display Memory: 766 MB
Dedicated Memory: 494 MB
Shared Memory: 271 MB
Current Mode: 1920 x 1200 (32 bit) (60Hz)
Monitor: Moniteur Plug-and-Play générique
Driver Name: nvd3dum.dll,nvapi.dll
Driver Version: 7.15.0010.9686 (English)
DDI Version: 9Ex
Driver Attributes: Final Retail
Driver Date/Size: 11/2/2006 10:46:12, 3022848 bytes
WHQL Logo'd: Yes
WHQL Date Stamp:
Device Identifier: {D7B71E3E-41DB-11CF-5A56-951001C2CA35}
Vendor ID: 0x10DE
Device ID: 0x029B
SubSys ID: 0x309F103C
Revision ID: 0x00A1
Revision ID: 0x00A1
Video Accel: ModeMPEG2_A ModeMPEG2_C ModeVC1_B ModeVC1_A ModeWMV9_B
ModeWMV9_A
Deinterlace Caps:

André M. Landreau