After installing a new tape-drive driver on Windows 2000 Server, the system blue-screens at logon with “IRQL_NOT_LESS_OR_EQUAL.” You must restore service quickly and safely. Which recovery action should you use first?

Introduction / Context:
The IRQL_NOT_LESS_OR_EQUAL stop error commonly indicates a faulty or incompatible kernel-mode driver. Right after a new tape driver installation, the priority is rapid restoration of service on a file server. Windows 2000 provides several rollback mechanisms; choosing the least invasive, fastest working option limits downtime.

Given Data / Assumptions:

• New hardware driver was installed immediately prior to BSOD.
• System boots to the point of applying the new driver, then fails.
• Users depend on this server during business hours.
• Goal: quick, reliable restoration without deeper repairs.

Concept / Approach:
Last Known Good Configuration restores the previous control set (services/drivers start list) used in the last successful logon. It is specifically designed for issues introduced by newly enabled drivers or services. It is fast, non-destructive, and often sufficient. Safe Mode or Recovery Console are valid but typically second-line options requiring manual removal/disable. Emergency Repair is more intrusive and slower.

Step-by-Step Solution:
1) Reboot and press F8 to access Advanced Options.2) Select “Last Known Good Configuration.”3) Allow Windows to boot using the prior control set (without the problematic driver).4) Once stable, uninstall or roll back the tape driver and obtain a correct version.

Verification / Alternative check:
Successful boot without the BSOD confirms the driver start entry was rolled back. Event logs should no longer show the tape driver loading. Perform a test backup only after reinstalling a verified driver.

Why Other Options Are Wrong:

• Emergency Repair: Heavier than needed and may modify system files broadly.
• Safe Mode / Recovery Console: Work, but take longer and require manual intervention; use if Last Known Good fails.

Common Pitfalls:
Repeatedly rebooting into normal mode (which sets the faulty control set as “good” if a logon occurs), making rollback harder; forgetting to re-test with a verified driver.

Final Answer:
Restart using Last Known Good Configuration