HP LJ475UT manual Software is functioning abnormally, Computer is on but not responding

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repeatedly, the image alternates among the computer display, one or more external displays, and simultaneous display on all devices.

Software is functioning abnormally

If the software is unresponsive or responds abnormally, restart the computer by clicking Computer > Shutdown > Restart. If you cannot restart the computer using this procedure, refer to the next section, The computer is on but not responding on page 78.

The computer is on but not responding

If the computer is turned on but is not responding to software or keyboard commands, try the following emergency shutdown procedures, in the sequence provided, until shutdown occurs:

CAUTION: Emergency shutdown procedures result in the loss of unsaved information.

Press and hold the power button for at least 5 seconds.

Disconnect the computer from external power and remove the battery.

The computer is unusually warm

It is normal for the computer to feel warm to the touch while it is in use. But if the computer feels unusually warm, it may be overheating because a vent is blocked.

If you suspect that the computer is overheating, allow the computer to cool to room temperature. Be sure to keep all vents free from obstructions while you are using the computer.

WARNING! To reduce the possibility of heat-related injuries or of overheating the computer, do not place the computer directly on your lap or obstruct the computer air vents. Use the computer only on a hard, flat surface. Do not allow another hard surface, such as an adjoining optional printer, or a soft surface, such as pillows or rugs or clothing, to block airflow. Also, do not allow the AC adapter to contact the skin or a soft surface, such as pillows or rugs or clothing, during operation. The computer and the AC adapter comply with the user-accessible surface temperature limits defined by the International Standard for Safety of Information Technology Equipment (IEC 60950).

NOTE: The fan in the computer starts up automatically to cool internal components and prevent overheating. It is normal for the internal fan to cycle on and off during operation.

An external device is not working

Follow these suggestions if an external device does not function as expected:

Turn on the device according to the manufacturer's instructions.

Be sure that all device connections are secure.

Be sure that the device is receiving electrical power.

Be sure that the device, especially if it is older, is compatible with the operating system.

Be sure that the correct drivers are installed and updated.

78 Appendix A Troubleshooting and support

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Contents HP Notebook User Guide Product notice Safety warning notice Iv Safety warning notice Table of contents VGA Drives Performing a system recovery Backing up your information Cleaning products Page Welcome Finding informationFinding information Resources For information aboutTop Getting to know your computerTouchPad Lights Control Center System Power Management ButtonsKeys Fn keyEsc key Front Right Left Left Display Bottom Networking Using an Internet service provider ISP Identifying wireless and network status icons Creating a wireless connectionUsing a Wlan Turning wireless devices on and offConnecting to an existing Wlan Setting up a new WlanProtecting your Wlan Roaming to another networkUsing Bluetooth wireless devices select models only Connecting to a wired networkUsing a modem select models only Connecting a modem cableConnecting a country- or region-specific modem cable adapter Connecting to a local area network LAN select models only Keyboard and pointing devices Using the keyboardIdentifying the hotkeys Using the keyboard Using keypads Using the embedded numeric keypadUsing the integrated numeric keypad Turning the embedded numeric keypad on and offUsing an optional external numeric keypad Using the TouchPadTurning the TouchPad off and on Navigating Using TouchPad gesturesSelecting Scrolling Setting pointing device preferencesPinching/Zooming Using the media activity keys MultimediaUsing the audio features Adjusting the volume Using the Webcam select models only Checking your audio functionsUsing video devices VGAConnecting an Hdmi device select models only Configuring audio for Hdmi select models only Power management Shutting down the computerSetting power options Using power-saving statesInitiating and exiting Suspend Initiating and exiting HibernationUsing battery power Using the Power iconUsing power management Viewing the current power management settingsDisplaying the remaining battery charge Inserting or removing the battery Charging a battery Managing low battery levels Maximizing battery lifeIdentifying low battery levels Storing a battery Conserving battery powerResolving a low battery level Disposing of a used battery Using external AC powerReplacing the battery Testing an AC adapter Drives Handling drivesReplacing or upgrading the hard drive Removing the hard driveLift the hard drive 3 out of the hard drive bay Drives Installing a hard drive Page Using optical drives select models only Identifying the installed optical driveInserting an optical disc Removing an optical discWhen the disc tray opens normally Page External cards and devices Using Digital Media Slot cards select models onlyInserting a digital card Removing a digital card Using ExpressCards select models only Configuring an ExpressCardInserting an ExpressCard Using a USB device Removing an ExpressCardConnecting a USB device Removing a USB deviceUsing optional external devices Using optional external drivesMemory modules Page Page Page Page Security Protecting the computerSetting passwords in the operating system Using passwordsSetting passwords in Computer Setup Entering an administrator password Managing an administrator passwordManaging a power-on password Using firewall software Entering a power-on passwordInstalling an optional security cable Backup and Recovery Performing a system recovery Backing up your informationPerforming a system recovery Backing up your information Computer Setup Starting Computer SetupUsing Computer Setup Navigating and selecting in Computer SetupUpdating the Bios Restoring factory settings in Computer SetupDetermining the Bios version Downloading a Bios updateTroubleshooting and support TroubleshootingComputer is unable to start up Computer screen is blankSoftware is functioning abnormally Computer is on but not respondingComputer is unusually warm An external device is not workingWireless network connection is not working Optical disc tray does not open for removal of a CD or DVDDisc does not play Computer does not detect the optical driveMovie is not visible on an external display Contacting customer support Labels ComponentCleaning your computer Cleaning productsSpecifications Input powerOperating environment Electrostatic discharge Index USBJacks