Motherboard/ Boot Loop Question....

I posted about this last month and exhausted every solution I could think of, but there's a new development I wanted to share that could maybe trigger a new solution.

I'm trying to rebuild my old workhorse Windows 7 machine and the system is practically bread-boarded at the moment. I'm trying to figure out why booting into any OS will cause a shut down right before it would traditionally ask for me to select a user (after the windows animated logo). The boot looping is driving me bananas and I don't want to give up.

Here's what I've tried:

• I removed the HD and tried to boot into Windows from two different installation disks (Legal copies of Home & Enterprise). It loops exactly the same as it does with the hard drive in & current OS.
• I tried all the native recovery options, plus I created & ran repair discs using both USB and an optical drive. All just rebooted.
• I can't install a fresh copy of windows, because it will reboot before it gives that option.
• I tried to disable automatic reboots, and it just reboots.
• I can't get into safe mode and can't get to a command prompt.
• I flashed the BIOS, reset the CMOS, checked the time & date
• I ran and passed a memory check, plus tried different configurations.
• I tried two different working video cards, Both seem to display fine.
• I tried THREE different compatible i7 processors, all of which I tried in other machines and are confirmed to be working properly. They all function the same.

The only thing that's "new" here is the motherboard (ASUS P7P55D-E). I'm familiar with this model, but it was harvested from another machine. It's showing no signs of not working correctly and everything boots very smoothly up to that Windows logo.

I'm thinking it is somehow the MB, but also what could possibly cause it to do this? Am I not thinking of something?

Ug. Help me Rhonda!

SIW2 said:

You tried updating the bios. Are you sure the psu is ok

Yup. I tired a brand new one; same response. I feel like PC is running really smooth too, which is driving me nuts. It's a quest at this point.

I solved the problem! In case anyone is trying to restore an old OS and finds themselves with similar symptoms, the error was caused by the way my BIOS handles ACPI.

5.0 was enabled by default, which is apparently known to cause power management instability issues with all Windows 7 media. ACPI 2.0 (compatible with W7) can be enabled in the BIOS, but disabling 5.0 causes a fatal error when booting. When I enabled them both, all W7 installations and rescue media would shut down before it reached any menus.

The solution:

1. Enable 2.0, Disable 5.0 and allow the error to happen.
2. Restart the system and enter the BIOS.
3. NOW enable ACPI 5.0 and allow the system to cycle and... boom. Works like a charm.

All W7 media wasn't working because the BIOS was configured to load 5.0 before 2.0, if they're both enabled together at the same time.
By first establishing 2.0 and then activating 5.0 on the next cycle, it allowed the OS to boot.

You can try a different PSU, check RAM slots, and inspect for short circuits.