So you’ve installed Windows Xp on a (probably very) old computer and forgot to check the BIOS to make sure APCI is enabled…
Now to switch Windows Xp from the “Standard PC” Hardware Abstraction Layer to the A(dvanced) C(onfiguration and) P(ower) I(nterface) one – so that things like standby/hibernation and auto-power off work – you’ve got two choices:
- Performs a repair install
- Follow the steps below:
Open Registry Editor and browse to
Right click the 0000 key and choose “Permissions…”. Check the “Full Control” checkbox for “Everyone”. This will give you control to edit this registry key.
Open the “HardwareID” value and change it from e_isa_up to acpipic_up (followed by one line break, the cursor should be on the line directly under “acpipic_up”).
Open Device Manager, open the “Computer” key, right-click “Standard PC”, and select “Update Driver”. You’ll pick from a list, don’t search, answer accordingly. Select the ACPI entry, which will now be shown in the Compatible Hardware list (joy!), thanks to the previous registry tweak.
If you actually CONTINUE with this and your system is NOT actually an ACPI system, it will become unbootable.
Select “Next” and let the new HAL install.
Reboot, and you’re done!
Since hal.inf locks you into only “compatible” HALs, you can now update again and select Multi-Processor PC if your system supports it, then you’ll have multi-cores.