How can I solve error 0x000000A5 when installing W7 on my laptop?

[blueshell]

After following SIW2's guide on updating my Windows 7 installation media and enabling legacy support on the Lenovo Legion UEFI menu, I tried to boot the updated installation USB drive. At first it seemed normal; the "Windows is loading files" screen showed up correctly and then the "Starting Windows" screen appeared, but it froze and gave me a BSOD with error code 0x000000A5 "The BIOS in this system is not fully ACPI compliant."

My laptop's specs are in my profile and the model number is 15IMH05H.

Any bit of help is appreciated.

 

[flavallee]

According to your "My Computer" specs, that Lenovo laptop is a 10th generation Intel model.
That's one reason why you can't get Windows 7 to install in it.

This is the support site for it - which has device drivers only for Windows 10.
laptops and netbooks :: legion series :: legion 5 15imh05h - Lenovo Support US

 

[SIW2]

Windows 7 can run fine on most 10th gen desktop mobos - separate graphics card required.

Laptops can present difficulties - not least because are no win7 igpu drivers for 10/11th gen.

The acpi error is likely something else, you could try a different acpi.sys...if I can find it.

here:
View attachment acpipatched-win7.zip
Windows 7 x64 on Lenovo IdeaPad 100-14IBY

 

[blueshell]

Where do I put the different acpi.sys?

 

[SIW2]

After following SIW2's guide on updating my Windows 7 installation media and enabling legacy support on the Lenovo Legion UEFI menu, I tried to boot the updated installation USB drive

acpi.sys lives in windows\system32\drivers

rename the existing acpi.sys to something like acpi.sys.old then copy in the new version.

Heres how:
ON your updated usb stick:

1. Rename sources\boot.wim to boot7.wim

2. Copy the entire contents of this iso 1904v3.iso onto your updated usb stick.

3. Then when you boot from the usb stick you will actually be booting a special windows 10 boot.wim

4. You can use the included winntsetup to install windows 7. Winntsetup is under the start menu of the booted media.
If you need to partition the target disk on the Lenovo, there are partition tools included.
After winntsetup has finished applying the win7 image, do not restart yet.
Copy the new acpi.sys into the windows\system32\drivers folder on the windows 7 partition.

Now try booting into the newly applied win7.