итак, проблема.
моя плата - IWILL dbd100, чипсет BX
после установки WINXP+SP1 возникла такая проблема, комп переодически перегружается.
ошибка такого рода:
ACPI BIOS Is Attempting to Write to Illegal IO Port Address
на сайте microsoft нашел:

Error Message: ACPI BIOS Is Attempting to Write to Illegal IO Port Address
Относится к
This article was previously published under Q283649
SYMPTOMS
The following error message may be in the system event log when you open the Event Viewer:

Source: ACPI Category: None Type: Error Event ID: 5 User: N/A Computer: Machine_Name Description: AMLI: ACPI BIOS is attempting to write to an illegal IO port address (0xnnnn), which lies in the 0xXXXX - 0xYYYY protected address range. This could lead to system instability. Please contact your system vendor for technical assistance.

For more information, see Help and Support Center at:
http://go.microsoft.com/fwlink/events.asp

Where nnnn is one of the following: Address or Range Description
0x000 – 0x009 ISA DMA
0x020 – 0x021 PIC
0x040 – 0x043 Timer1, Refresh, Speaker, Control Word
0x048 – 0x04B Timer2, Failsafe
0x070 – 0x071 CMOS/NMI enable
0x074 – 0x076 Extended CMOS
0x081 – 0x083 DMA
0x087 DMA
0x089 DMA
0x08A – 0x08B DMA
0x08F DMA
0x090 – 0x091 Arbitration Control Port, Card Select Feedback
0x093 – 0x094 Reserved, System board setup
0x096 – 0x097 POS channel select
0x0A0 – 0x0A1 Cascaded PIC
0x0C0 – 0x0DF ISA DMA
0x4D0 – 0x4D1 Edge, level control registers for PIC
0xCF8 – 0xCFF PCI Configuration Space Access Pair

CAUSE
This behavior may occur if your computer's basic input/output system (BIOS) tries to write to one of the earlier ports by using an AML [Advanced Configuration and Power Interface (ACPI) Machine Language] System IO operation region. Your try may be blocked by Windows XP because accessing these ports by using this mechanism is deemed dangerous and can cause system instability. This feature is designed to improve the stability of your computer's operating system.
STATUS
This behavior is by design.

Contact the BIOS vendor for a possible BIOS update. For more information see the following Microsoft Web site:
http://support.microsoft.com/default.aspx?scid=http%3a%2f%2fwww.microsoft.com%2fHWDEV%2fOnnow%2fBIOSAML.htm

The information in this article applies to:
Microsoft Windows XP Professional
Microsoft Windows XP Home Edition
Last Reviewed: 10/30/2003 (1.1)
Keywords: kberrmsg kbHardware kbprb KB283649

как я понимаю, проблема в старом биосе.
если бы Вы могли пропатчить биос от мамок БХ от этой напасти, то уверен много народу Вам бы было оч. благодарна :)