LabQuest does not respond and the screen and power light are black.

Connect the LabQuest to AC power in case the battery level is very low. Confirm that the AC outlet you use is live. Let the unit charge for a minute or so, and leave the AC adapter connected. Press the power button. This will usually revive an unresponsive LabQuest. If that was the problem, let the unit charge for eight hours or more to fully restore the battery. There is no harm in leaving the unit charging indefinitely.

There are a few other things that could cause a LabQuest to stop responding. In most cases, LabQuest is a lot like a computer and simply rebooting the device will solve the problem. If the screen is black and the power button does not work, the only option is to do a hard reset. See

     TIL 1777: How do I reboot or reset a LabQuest?

There are other circumstances in which you might need to do something else, or that a reboot is not necessary:

     TIL 1776: My LabQuest screen is unresponsive or acts like I am tapping on the wrong spot.
     TIL 1779: LabQuest blue power button LED ring stays on, but the screen is black.
     TIL 1795: LabQuest hardkeys (buttons) do not respond.
     TIL 1789: LabQuest Screen is white, does not respond
     TIL 1872: LabQuest gets stuck on the "System is rebooting" screen when trying to reboot.

If none of these steps help, contact Vernier technical support to arrange repair of the unit.