Instalar Snow Leopard en XPS 420

I am trying to install Snow Leopard on my Dell XPS 420 with all the tutorials and images that I found on different forums and although I isntalacion starts at the end I get the "apple" with the sign above prohibited.
I installed an image of Hazard for XPS 420 with graphic Navidi but mine is an ATI Radeon HD 420 TX and not loading restart Snow.
Deputy Aida64 report with data from my pc, if anyone has the solution.
Thanks in advance.

Versión AIDA64 v1.60.1300/es
Módulo de rendimiento 2.7.345-x64
Página Web AIDA64 | PC Benchmark | System Diagnostics | Network Inventory
Tipo de informe Informe rápido [ TRIAL VERSION ]
Computadora JUAN-PC
Generador Juan
Sistema operativo Microsoft Windows 7 Ultimate 6.1.7600 (Win7 RTM)
Fecha 2011-04-10
Hora 18:06


Chipset

[ Northbridge: Intel Beachwood X38 ]

Propiedades del Northbridge:
Northbridge Intel Beachwood X38
Velocidades de FSB soportadas FSB800, FSB1066, FSB1333
Tipos de memoria soportadas DDR2-667, DDR2-800, DDR3-800, DDR3-1066, DDR3-1333 SDRAM
Cantidad máxima de memoria 8 GB
Revisión / Stepping 00 / A0
Forma del componente 1300 Pin FC-BGA
Tamaño del componente 4.0 cm x 4.0 cm
Voltaje del núcleo 1.25 V
In-Order Queue Depth 12

Controlador PCI Express:
PCI-E 2.0 x16 port #2 En uso @ x16 (ATI Radeon HD 2600 - High Definition Audio Controller, ATI Radeon HD 2600 XT 256MB GDDR4 (Dell) Video Adapter)
PCI-E 2.0 x16 port #3