HOW TO: Add Support for Multiple Processors in Windows 2000

Windows 2000 provides support for single or multiple Central Processing Units (CPU); however, if you originally installed Windows 2000 on a computer with a single CPU, the hardware abstraction layer (HAL) on your computer must be updated for your computer to recognize and use multiple CPUs. This article describes how to add support for multiple processors in Windows 2000. In Microsoft Windows NT 4.0, you can use the Uptomp.exe tool to add support for multiple CPUs. The Uptomp.exe tool is not used in Windows 2000, instead, you can use Device Manager to make these changes. Note that before you change the computer type, contact your computer manufacturer to determine if there is a vendor-specific HAL that you should use instead of the standard HAL that is included in Windows 2000.

Installing Support for Multiple CPUs

1. Click Start, point to Settings, point to Control Panel, and then click System.
2. Click the Hardware tab, and then click Device Manager.
3. Double-click to expand the Computer branch. Note the type of support that you currently have.
4. Double-click the computer type that is listed under the Computer branch, click the Drivers tab, click Update Driver, and then click Next.
5. Click Display a list of known drivers for this device, and then click Show all hardware of this device class.
6. Click the appropriate computer type (do not change from non-ACPI to ACPI computer types), click Next, and then click Finish.

The following table lists and describes each HAL. NOTE: You can use this procedure only to upgrade from a single-processor HAL to a multiple-processor HAL. If you use this procedure to change from a standard HAL to an ACPI HAL (for example, after a BIOS upgrade) or vice-versa, unexpected results may occur, including an inability to boot the computer.

For additional information how to troubleshoot Windows 2000 HAL issues, click the article number below to view the article in the Microsoft Knowledge Base: