This article describes how to force in a system Hardware Abstraction Layer (HAL) during an upgrade or an installation of Microsoft Windows XP.

Note The procedure to change from the Standard PC HAL to the Advanced Configuration and Power Interface (ACPI) HAL differs in Windows XP from the procedure that Microsoft Windows 2000 uses.

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The HAL is computer code in Windows XP that makes it possible for Windows XP to run on a variety of different computer types. The HAL manipulates the computer hardware directly. During an upgrade or an installation of Windows XP, you can “force in” a HAL by pressing the F5 key, and then selecting from the available computer types.

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Upgrade from Microsoft Windows 2000 to Windows XP

When you upgrade from Windows 2000 to Windows XP, the HAL is preserved. For example, if the HAL on the Windows 2000-based computer is a Standard PC HAL, that HAL is reinstalled when you upgrade to Windows XP.

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In-place upgrade of Windows XP

When you perform an in-place upgrade, or a reinstallation of Windows XP, if the Setup program detects that you have an unsupported HAL installed for your computer type, and the Setup program determines that a HAL that supports that computer type must be installed, it installs the correct HAL. When this issue occurs, the HAL is changed from what was previously installed.

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Force in a system HAL

To prevent Windows XP from automatically determining the system HAL during the upgrade or the installation of Windows XP, you can manually force in a system HAL. To force in a system Hardware Abstraction Layer (HAL) during an upgrade or installation of Windows XP, follow these steps:

1.

During the Text-mode phase of the Setup program, when you receive the following message across the bottom of the screen, press F5: Press F6 if you have to install a third-party SCSI or RAID driver. Note If you press F7, the Standard PC HAL loads and the ACPI compliance check is bypassed.

2.

You receive the following list of computer types. A brief description of each HAL is included here: • ACPI Multiprocessor PC Applies to a multiple-processor ACPI computer. • ACPI Uniprocessor PC Applies to an ACPI multiple-processor board but with a single processor installed. • Advanced Configuration and Power Interface (ACPI) PC Applies to a single processor motherboard with single processor. • Compaq SystemPro Multiprocessor or 100% Compatible Applies to a Compaq SystemPro computer. • MPS Uniprocessor PC Applies to non-ACPI computers dual processor motherboard with a single processor installed. • MPS Multiprocessor PC Applies to non-ACPI computers with a dual processor running. • Standard PC Applies to any Standard PC, non-ACPI, or non-MPS. The CPU may be a 386, a 486, a Pentium, a Pentium II, or a Pentium III. • Standard PC with C-Step i486 • Other

Note The screen displays only two computer types at a time. To scroll up or down to view the complete list, use the arrow keys.
For additional information about related topics, click the following article numbers to view the articles in the Microsoft Knowledge Base:

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