Vista installation freezes after "Windows is loading files..." scr

Hi, I intend to buy Windows Home Premium to install on my PC, but to be shure
all my hardware is going to work properlly with it, I'm trying to install
Vista Beta.
At first I creatted a virtual PC to test the Beta version, and it worked
perfectly. But when I try to install it on my HD... no way... I boot my PC
with installation DVD in the drive. The installation begins, the screen
"Windows is loading files..." is shown, and when the next screen starts to
appear (with a progress bar and the text "(C) Microsoft Corporation", the
system freezes.
I tried to start installation by Windows XP too. Then it's possible to
choose the partion, the files copying starts, but after the fisrt boot, to
continue installation, the system freezes in the same screen.
Some people told me to try replacing my memory chips, but the problem
persisted.
Any idea on what can I try?

P.S.: I have Windows XP installed, to use dual boot.

Intel Core 2 Duo 6600 (2.40 GHz)
MoBo Asus P5D WH Deluxe
2 GB RAM (2 x 1GB RAM DDR2 667 MHz Samsung)
HD SATA2 250GB
Video Card nVidia GeForce 7600GT
LCD Samsung 713N with VGA connector adapted to the video card DVI connector

Tks!