Error Message:

IRQL_NOT_LESS_OR_EQUAL

Explanation:

This Stop message indicates that a kernel-mode process or driver attempted to access a memory address to which it did not have permission to access. The most common cause of this error is an incorrect or corrupted pointer that references an incorrect location in memory. A pointer is a variable used by a program to refer to a block of memory. If the variable has an incorrect value in it, the program tries to access memory that it should not. When this occurs in a user-mode application, it generates an access violation. When it occurs in kernel mode, it generates a STOP 0x0000000A message. If you encounter this error while upgrading to a newer version of Windows, it might be caused by a device driver, a system service, a virus scanner, or a backup tool that is incompatible with the new version.

User Action:

This error usually occurs after the installation of a buggy device driver, system service, or BIOS. To resolve it quickly, restart your computer, and press F8 at the character-mode menu that displays the operating system choices. At the resulting Windows 2000 Advanced Options menu, choose the Last Known Good Configuration option. This option is most effective when only one driver or service is added at a time. If you encounter this error while upgrading from Windows NT 4.0 or earlier, it might be caused by a device driver, a system service, a virus scanner, or a backup tool that is incompatible with the new version. If possible, remove all third-party device drivers and system services and disable any virus scanners prior to upgrading. Contact the software manufacturers to obtain updates of these tools. For additional error messages that might help pinpoint the device or driver that is causing the error, check the System Log in Event Viewer. Disabling memory caching of the BIOS might also resolve this error. You should also run hardware diagnostics supplied by the system manufacturer, especially the memory scanner. For details on these procedures, see the owners manual for your computer. If your system has small computer system interface (SCSI) adapters, contact the adapter manufacturer to obtain updated Windows 2000 drivers. Disable sync negotiation in the SCSI BIOS, check the cables and the SCSI IDs of each device, and confirm proper termination. For enhanced integrated device electronics (EIDE) devices, define the onboard EIDE port as Primary only. Also, check each EIDE device for the proper master/slave/stand-alone setting. Remove all EIDE devices except for hard disks. If the message appears during an installation of Windows 2000, make sure that the computer and all installed peripherals are listed on the Microsoft Windows 2000 Hardware Compatibility List (HCL) on https://www.microsoft.com. For more troubleshooting information about this Stop message, refer to the Microsoft Knowledge Base at https://support.microsoft.com/support.