ACPI compliance

How Windows XP Determines ACPI Compatibility
http://support.microsoft.com/kb/314088

Since this is an older system I presume Windows XP has no problems installing?
Disconnect all external devices
If you are using a USB Mouse and Keyborad and have an older PS2 Mouse/Keyboard try them as well. 

Hi Aswen,

Welcome to Microsoft Answers.

As you are getting the error message that the BIOS is not fully ACPI compliant I would suggest you to contact the manufacturer for updates on BIOS. You may refer to the below mentioned link and check if this helps -
http://www.ecs.com.tw/ECSWebSite/Downloads/ProductsDetail_Download.aspx?detailid=81&DetailName=New&DetailDesc=&CategoryID=1&MenuID=6&LanID=0

The only way you will be able to install Windows 7 is making the BIOS, ACPI compliant and then install Windows 7. Refer to the link mentioned below for contact the manufacturer support -
http://www.ecs.com.tw/ECSWebSite/Support/Category_Support.aspx?MenuID=3&LanID=0

Also the motherboard does not show compatibility with Windows 7 as listed below -
http://www.microsoft.com/windows/compatibility/windows-7/en-us/Search.aspx?type=Hardware&s=ECS%20socket%20462%20K7AMA%20V1.5

I would suggest you to download and use the upgrade advisor and check for more details. Refer to the below link for guidance -

http://windows.microsoft.com/en-us/windows/downloads/upgrade-advisor

Hope this helps. Let us know the results.
Thanks,
Meghmala – Microsoft Support

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