Lenovo ThinkPad E450, User Manual, Page: 107 / 166

Solution : The numeric lock function is on. To disable it, press Fn+NumLock.
• Problem : All or some keys on the external numeric keypad do not work.
Solution : Make sure that the external numeric keypad is correctly connected to the computer.
Problems with the display and multimedia devices
This topic includes the most common problems with displays and multimedia devices, including the
computer display, the external monitor, and audio devices.
Computer screen problems
• Problem : The screen is blank.
Solution : Do the following:
– Press the brightness-up key to bring up the image.
– If you are using the ac power adapter, or using the battery and the battery gauge shows that the battery
is not depleted, press the brightness-up key to make the screen brighter.
– If your computer is in sleep mode, press Fn to resume from the sleep mode.
– If the problem persists, follow the solution for the following problem.
• Problem : The screen is unreadable or distorted.
Solution : Make sure that:
– The display device driver is installed correctly.
– The screen resolution and color quality are correctly set.
– The monitor type is correct.
To check these settings, do the following:
1. Connect the external monitor to your computer, and then connect the monitor to an electrical outlet.
2. Turn on the external monitor.
3. Right-click on the desktop, and click Screen resolution .
Note: If your computer cannot detect the external monitor, click the Detect button.
4. Select the external monitor and set Resolution .
5. Click Advanced Settings .
6. Click the Monitor tab. Check the monitor information to make sure that the monitor type is correct.
If the monitor type is correct, click OK to close the window; otherwise proceed with the following steps.
1. If more than two monitor types are displayed, select Generic PnP Monitor or Generic Non-PnP
Monitor .
2. Click Properties . If you are prompted for an administrator password or confirmation, type the password
or provide confirmation.
3. Click the Driver tab.
4. Click Update Driver .
5. Click Browse my computer for driver software , and then click Let me pick from a list of device
drivers on my computer .
6. Clear the Show compatible hardware check box.
7. Select the correct manufacturer and model for the external monitor. If you cannot find your monitor on
the list, stop the installation of this driver and use the driver shipped with your monitor.
Chapter 8
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Troubleshooting computer problems
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