Start X hangs the computer

[Javier Matos]

Hello, I was searching about my problem in a lot off forums but I don´t find 
a solution... .

I Install FreeBSD 6.0 in my box (I have 2 boxes and FreeBSD was installed in 
both). The first one work fine with all
the configuration that I make but the second (boxes are different) have 
problems because I can start "startx", "xdm"
and "kdm" and it show the screen for a while with the correct resolution but 
then the screen freeze and after some
seconds the box restart... . I can´t find any reason for this behaviour 
because log files seems to show that all is
working. I follow the same steeps with two boxes but only one can run X.

The box who crashes is a P5GD1_PRO (Intel 915P chipset), my graphic card is 
a GeForce FX 6200 (PCI-Express).

Anyone have any idea about the what is the problem?