The Role of the F5 Key and Shutdown Problems
When I first put this page together I meant to include this information. Unfortunately it totally slipped my mind. One of the hazards of being an Elder(ly) Geek, but better late than never. Thanks to reader Glen M. for jogging my memory.
When XP is first installed it tries to determine what type of BIOS is available on the computer. Newer systems have what is known as Advanced Configuration and Power Interface (ACPI) capability. Unfortunately, XP doesn't always recognize a computer BIOS is ACPI capable and doesn't install the support for ACPI. Even more unfortunate is the fact that if ACPI support isn't determined at the initial install it's virtually impossible to correct this at a later time short of reinstalling XP over the top of the previous XP installation. To do so requires changing the Hardware Abstraction Layer (HAL). The chances of successfully changing a HAL after XP has been installed is pretty close to zilch.
Once you drop the CD in the tray and fire up the computer to install XP, the first thing you'll see at the bottom of the screen is the option to press F6 if you need to install a SCSI or RAID controller. Don't press F6. Press F5 instead. This will take you to a separate menu of Hardware Abstraction Layer's where you can choose an appropriate HAL that supports ACPI. The choices will be:
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ACPI Multiprocessor PC
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ACPI Uniprocessor PC
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Advanced Configuration and Power Interface (ACPI) PC
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Compaq SystemPro Multiprocessor or 100% Compatible PC
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MPS Uniprocessor PC
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MPS Multiprocessor PC
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Standard PC
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Standard PC with C-Step i486
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Other
In the majority of installations the 'Advanced Configuration and Power Interface (ACPI) PC' HAL is the one you will want to use. A few cautions are also in order:
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Obtain and install the latest BIOS for your motherboard before you begin the XP installation.
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Equally as important as using the proper HAL on ACPI capable systems, is NOT using it on systems that are not ACPI compatible. The install may complete but the system will almost surely fail to start when it reboots.
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There are situations where it is definitely not desirable to use an ACPI HAL even if it is supported by the BIOS. This predominately applies to servers, but to ensure that an ACPI HAL will not be used or automatically detected and used, press F7 instead of F5 as discussed previously.
Considering the number of problems that users have with systems not shutting down completely I wonder why this feature is not prominently mentioned and documented. It could save many headaches, but now you know. A good piece of knowledge to have tucked away for your next XP install.
As a final note, to determine if your computer was detected as being ACPI enabled:
Right click My Computer then click Properties > Hardware > Device Manager.
Expand the entry called Computer.
If the entry is 'Advanced Configuration and Power Interface (ACPI) PC' you're all set. If it says 'Standard PC' the computer BIOS was not detected as being ACPI capable.
