Phone has no display and turns off when I press any key

Performing a hard reset deletes all of your user data, which includes pictures, videos, and music saved to your internal memory. Please make sure to back up your information prior to performing a hard reset.

1. Turn the phone off.
2. Press and hold the following keys at the same time: Volume Down Key + Power/Lock Key on the back of the phone.
3. Release the Power/Lock Key only when the LG logo is displayed, then immediately press and hold the Power/Lock Key again.
4. Release all keys when the Factory hard reset screen is displayed.
5. Press the Power/Lock Key to continue or either of the Volume Keys to cancel.
6. Press the Power/Lock Key once more to confirm or either of the Volume Keys to cancel.

You need to reset your phone

If the handset is locked, frozen, or unresponsive, you can hard reset it using the hardware keys instead of the menu.

A hard reset restores the original factory settings and erases content, including downloaded ringtones, images, programs, and contacts stored in the internal memory. This feature allows for resetting of sound profiles, display settings, and phone or memory card settings.

To perform a hard reset using the hardware keys, follow these steps:

Save any open files, and back up all necessary data on the internal memory if the device is responsive and can synchronize files. See: Prepare for a master reset and back up data on Android

Turn off the phone.

Note: If the phone is unresponsive and does not turn off, remove the battery and then re-insert it.

Hold down the Volume Up, Volume Down, and Power keys simultaneously.

When the Samsung log appears, continue to hold the keys until the master reset menu appears.

Press the Volume Down key to select Delete all user data when the Android master reset menu appears.

Press the Power key to confirm your selection.

Press the Volume Down key to select Yes – delete all user data.

Press the Power key to confirm your selection.

Press the Power key to select reboot system now.

If you forget your lock sequence and backup PIN, you will have to perform a hard reset to gain access to your phone.
WARNING! Performing a hard reset deletes all of your user data, which includes pictures, videos, and music saved to your internal memory. Please make sure to back up your information prior to performing a hard reset.

1. Turn the phone off.
2. Press and hold the following keys at the same time: Volume Down Key + Power/Lock Key on the back of the phone.
3. Release the Power/Lock Key only when the LG logo is displayed, then immediately press and hold the Power/Lock Key again.
4. Release all keys when the Factory hard reset screen is displayed.
5. Press the Power/Lock Key to continue or either of the Volume Keys to cancel.
6. Press the Power/Lock Key once more to confirm or either of the Volume Keys to cancel.

If you are unable to operate the phone at then the last option that you can do is to hard reset the phone, please take note that this procedure will delete everything on the phone. Please follow steps below:

Back up data on the internal memory.
Turn off the device.
Press and hold the Volume Up key and the Home key, then press and hold the Power key.
When the Samsung GALAXY GRAND Prime logo screen displays, release only the Power key
When the Android logo displays, release the Volume Up and the Home key ('Installing system update' will show for about 30 - 60 seconds before showing the Android system recovery menu options).
Press the Volume down key several times key to highlight 'wipe data / factory reset.'
Press Power key to select.
Press the Volume down key until 'Yes -- delete all user data' is highlighted.
Press Power hey to select and start the master reset.
When the master reset is complete, 'Reboot system now' is highlighted.
Press the Power key to restart the device.

Back up all necessary data on the internal memory.

If the handset is locked, frozen, or unresponsive, you can hard reset it using the hardware keys instead of the menu.

A hard reset restores the original factory settings and erases content, including downloaded ringtones, images, programs, and contacts stored in the internal memory. This feature allows for resetting of sound profiles, display settings, and phone or memory card settings.

To perform a hard reset using the hardware keys, follow these steps:

Save any open files, and back up all necessary data on the internal memory if the device is responsive and can synchronize files. See: Prepare for a master reset and back up data on Android

Turn off the phone.

Note: If the phone is unresponsive and does not turn off, remove the battery and then re-insert it.

Hold down the Volume Up, Volume Down, and Power keys simultaneously.

When the Samsung log appears, continue to hold the keys until the master reset menu appears.

Press the Volume Down key to select Delete all user data when the Android master reset menu appears.

Press the Power key to confirm your selection.

Press the Volume Down key to select Yes – delete all user data.

Press the Power key to confirm your selection.

Press the Power key to select reboot system now.

try this Recovery
Solution
Factory data
reset
How do I perform a
Factory data reset?
Resetting the phone does not erase
any system software updates you have
downloaded or any files on your microSD
card or internal memory, such as music
or photos. And so, if you want to erase
all the data on the internal memory while
resetting the phone, select the check box
of Erase internal memory.
•
Recovery
Solution
Hard Reset
(Factory Reset)
How can I perform a
factory reset if I can't
access the phone's
setting menu?
How to perform a Hard Reset (Factory Reset):
1. Turn the power off.
2. When the phone is switched off, press and
hold the Volume down key + Home key
with your left hand. Then press the Power
key while pressing Volume down key +
Home key.
3. LG logo would be displayed in 1~2
seconds then the phone would re-boot
showing android robot animation. Finally
the factory reset would be processed.
Attention:
If a factory reset is performed, all
installed applications and user data will
be erased. Please remember to back up
any important data before performing a
factory reset.

Steps to reset phone using hardware keys

This restores the original factory settings and erases all downloaded content, including ringtones, images, programs, and contacts stored in the internal memory.

Turn the phone OFF.
Turn on the device by holding both the Volume Up key and Volume Down key while pressing the Power key.
When the Android System Recovery screen displays, release the keys.
Using the volume keys, scroll to Wipe Data / Factory Reset.
Press the Power key to confirm.
Using the volume keys, scroll to Yes - Delete all user data.
Once complete, press the Power key.
Once complete, press the Volume Down key to scroll to Reboot System Now.
Press the Power key to confirm.

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Hard or master reset

A hard reset restores the original factory settings and may erase all downloaded content, including ringtones, images, programs, and contacts stored in the internal memory. To perform a hard reset, follow these steps:

1. Back up all necessary data by copying any files you want to save from your phone to your computer.
2. From the Start screen, swipe left.
3. Tap Settings.
4. Tap about.
5. Tap reset your phone.
6. Tap yes.

Hard or master reset using hardware buttons

If the phone is locked, frozen, or unresponsive, you can hard reset it using the hardware keys instead of the menu. A hard reset restores the original factory settings and may erase all downloaded content, including ringtones, images, programs, and contacts stored in the internal memory. To perform a hard reset using hardware keys, follow these steps:

1. Back up all necessary data by copying any files you want to save from your phone to your computer.
2. With the phone turned off, press and hold the Volume Up and Volume Down keys.
3. While still pressing the Volume keys, quickly press the Power/Lock key.
4. When the device displays 'This operation will delete all your personal data, and reset all settings to manufacturer default. Press Vol Down to restore manufacturer default, or press other keys to cancel.', release the Volume keys.
5. Press the Volume Down key to reset the device.

http://depts.washington.edu/uwmcdir/spectralink.html Correcting Spectralink Errors Below are instructions on performing a “soft test” which will correct any internal error 8 and 4444-444C messages on your Spectralink phone. To aid you in educating your staff you may view the following Word document showing the step-by-step instructions. Please feel free to print and post this document where the Spectralink phones are kept on your floor. Soft Test Instructions

1. Power off the phone.
2. Press and HOLD the volume key (VOL) and the power key at the same time (the phone will chirp and display the serial number.)
3. Now…release ONLY the power key (phone will vibrate and make a long tone.)
4. Now release the volume key (the display will have a lot of black boxes and ZZZZ’s – you will also see the bottom of the display showing “msg”, “bat”, etc.)
5. Count to three and then power off the phone.

This “soft test” is to correct only certain internal error messages. When the phone is experiencing a correctable error the display will read “internal error 8” or “internal error 4444-444C”. For all other internal errors the phone will need to be taken to Teleservices, NE-165 to be replaced.

2 ways.
First way is a “User rated” method. That is: To turn off the ringer for that phone. Note that you will also have no ringing for internal calls as well.
Press:
[Shift key] until the RING displays above the [S2] key, press it and use the jog dial to turn off the ringer. Do the reverse to turn it on again.
Some users will turn on [Auto Answer] so they can still receive internal calls.

The 2nd way is in “Installer Programming” and will require a certified dealer/technician turn off ringing to that phone on that (or any) line/s.