ACPI in Win XP ON a 748lmrt/ Urgent Help

[Nachotex]

Hi, I`m from chile... and i`m very happy because finally i found a place were all my questions have a hope for being solved.
Well Here are the Spec. of my pc, and then comes the problem:
Motherboard-748 Lmrt Pc Chips
Processor- Intel Pentium 3 Xeon 500 Mhz
192 MB Ram
HD-20 Gb western Digital
Power Supply - AT/ NON- ATX
BIOS Date - 14/09/2001 The last released that i Know.

1.-PROBLEM ONE: Well, all began when i decide to install The XP OS on my pc.
First i went to the bios setup and configure the power management to ACPI, the i went to the pci devices and setup the primary graphics adapter as AGP and activated the irq assignment and the plug and play option. Well i install Windows xo Without a problem, but the problem is the next when i shutdown my Computer; all programs are closed and when the screen that says Windows XP is Shutting Down appears, my Computer get Freeze.
2.- PROBLEM TWO: I can´t turn my computer onto suspend mode, the option is not available for me, when i saw this i thought that the problem could be that i might not have activated the irq assignmente in the bios for the vga primary graphics adapter, but i did it, then i didn´t know what to do so i download the sisoft sandra 2002 software, because a friend told me that this software sould help me, well in all the options of the program bios settings, vga adapters, motherboard i see the next notice "You need to check your bios settings, because they are wrong" then in the primary graphic screen of the sisoft sandra software i see The next Warning " Video card does not have an interrupt assignment".

Well thats all I think, plz i need your Help I`m from chile and you guys of the wimsbios Forum are my only Hope.

Note: Also The sisoft sandra and windows xp system information couldn determine any info about the vga card bios, In the official web site of sis enterprises i found a Vga Bios Update Named TSR file but i don´t Know how to use it for the vga bios upgrade. Well i think that this the major info that i can tell to you Guys, PLZ you got help me.
PLz.