This information pertains to the original LabQuest.

If you have LabQuest 2, see this article.
If you have LabQuest 3, see this article.

Apply the LQ1.7_Reset_Defaults update to restore factory defaults for an original LabQuest. This update does the following:

System Changes
     Updates to LabQuest version 1.7
     Resets Device Name to LabQuest
     Resets Regional Setting (language) to English

Stored File Changes
     Removes all stored files (LabQuest App and Sound Recorder App files)
     Restores the 102 Lab Instructions included with the original unit
     Removes any user added Lab Instruction files (from the LabQuest Library)

Resets User Settings
     Viewer Setup
     Light & Power

Removes Network Configurations
     Printer Settings
     Wi-Fi Setting (if using Wi-Fi dongle)

Download the update to Reset to Defaults: