Windows XP won't boot after installing SP2 – a BIOS update may be necessary

by Mark Kaelin | Aug 31, 2004 7:00:00 AM

Tags: Microsoft Windows XP Service Pack 2, Microsoft Windows, Mark Kaelin, BIOS, Service Pack 2, motherboard, Microsoft Windows XP

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Takeaway: Installing Microsoft Windows XP Service Pack 2 on a PC with a "Prescott" CPU and certain chip sets can cause it to fail to reboot completely. The problem can be solved with a workaround or a BIOS update.

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Windows XP Service Pack 2 (SP2) is a complex update with many ramifications for IT pros. TechRepublic's Windows XP Service Pack 2 Quick Guide drills down on critical SP2 need-to-know areas, with sections on fundamentals, changes that occur after installation, deployment procedures, problem areas, and removal.

Problem

Depending on the chipset, motherboard manufacturer, BIOS version, and CPU, installing Microsoft Windows XP Service Pack 2 can result in an unbootable computer system. The problem is generally associated with Intel "Prescott" CPUs and its chipsets, but not every such combination will cause a problem. As of this writing, motherboards exhibiting the behavior include:

Albatron PX865 PE Pro
Shuttle SB61G2
Jetway i875P
Soyo P4I865P
Aopen AX4SG Max
Asus P4P800-E deluxe
Abit IS7-V
Foxconn 865A01-G-6EKRS

Technically speaking, the problem revolves around the machine's BIOS not installing a production level microcode update. To check whether the BIOS is at the correct level, download the Intel Processor Frequency ID utility. The microcode version is identified by this utility as CPU Revision, which should equal at least 8.

Solution 1

If the Intel utility shows that you have the wrong microcode version, the primary solution to the problem is to update the system BIOS for your motherboard before you install SP2. Here are some motherboard manufacturer links:

BIOS updates

BIOS updates can be dangerous—please follow the manufacturer's instructions very closely to avoid a major catastrophe.

Solution 2

If you have already installed XP SP2 and have a PC that will not boot because of this microcode version problem, there are two workarounds you can try to get to a bootable state.

In the BIOS setup you should temporarily disable the L1 and L2 cache. On some motherboards, this will allow the computer to boot. You should then remove SP2, turn the L1 and L2 cache back on, and then update the BIOS to reflect the correct microcode version. After completing these steps, you should be able to re-install SP2 without running into this particular problem again.

If disabling L1 and L2 cache does not work, you can use a second workaround suggested by a representative at Intel: Boot the problem computer with an alternative OS or to the safe mode command line if possible. Assuming you can get to the Windows directory on the boot partition, navigate to this file and change its name so that it does not load the next time the machine is booted:

windows\system32\drivers\update.sys

After rebooting you should be able to install XP SP2, but keep in mind this is a temporary fix—the system will be unstable until you update the BIOS and reactivate the update.sys file.

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