Hi,Have you made any changes to your computer?Method 1:Step 1:Are you able to boot your computer in normal mode?I would suggest you to check in safe mode.' A description of the Safe Mode Boot options':Step 2:If you are able to boot your computer in safe mode, I would suggest you to perform clean boot and check.How to configure Windows XP to start in a 'clean boot' stateSteps to configure Windows to use a Normal startup stateAfter you used the clean boot to resolve your problem, you can follow these steps to configure Windows XP to start normally.1.
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Click Start, and then click Run.2. Type msconfig, and then click OK.The System Configuration Utility dialog box is displayed.3.
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Click the General tab, click Normal Startup - load all device drivers and services, and then click OK.4. When you are prompted, click Restart to restart the computer.Method 2 'Stop error code 0x000000D1 (DRIVERIRQLNOTLESSOREQUAL)' error message when you start your Windows XP-based computerAlso refer: Stop error message on a Windows XP-based computer: 'STOP 0x000000D1'Bug Check 0xD1: DRIVERIRQLNOTLESSOREQUAL.