Windows refuses to recognize ACPI

I am 100% sure my motherboard is ACPI, it was working with ACPI just last month. Windows recently just recently started giving me issues, so I thought I'd buy myself a few upgrades and re-install windows. I got a new PSU, hard drive, and RAID controller. Installed them all, and went to reinstall.
I got the issue with the setup hanging on "Setup is starting windows", so I tried to use f5 to select the HAL manually. It hangs on the same thing every time I tell it to use ACPI, but standard computer works fine. I tried to revert the hardware to how it was before, but it's still doing the same thing no mater what hardware configuration I have. I installed it all the way with using APM, and tried to force windows to ACPI with device manager, but the only thing it allows me to select is "Standard PC".
So my question is, how the heck should I get windows to recognize my ACPI?

 

Aside from a BIOS update, not much.

 

The BIOS is up to date, the last update was 2006. And it was working fine before.

 

The important thing to realize here is, it doesnt matter if it was working before, only that it doesn't now.

The Windows files on the CD have not changed. Therefore, the only thing that has changed is hardware. That can be in the form of hardware failure, changes, or even settings that have been changed. If you have reverted this machine exactly back to the state before and it still doesn't work...well what is left?

Try the clear cmos jumper and see where that gets ya. There isn't much left. There are no ways to force ACPI if it wont work when Windows tries to detect hardware compatibility with it.

 

I took out everything, except the original hard drive, 1 cd drive, 1 stick of ram, and the power supply.

 

Try the suggestion in my post, please.

 

Alright, I did a bios update, then tried windows.. same thing. Then I took out the battery for 10 minutes, put it back in, and same thing again.

I then tried to boot into a Slax linux Live CD, and ACPI worked perfectly in there. =/

 

Post your motherboard specs please. Brand, model, and BIOS version.


Thanks.

 

Asus P5RC-LE
It's from HP, they reference to it as the Altair-GL8.

The BIOS version is 3.03.

There's a whole detailed page about it here:
http://h10025.www1.hp.com/ewfrf/wc/...21&lc=en&cc=us&dlc=en&product=3262012&lang=en