Samsung SCH-U820 screen not working

Other than a bad digitizer (touchscreen) or connection, sometimes just a tiny bit of gunk/debris gets in that tiny gap that goes around the outside of the screen. That often results in the same problem,, a non-working touchscreen. Take a very thin edged piece if cut plastic as a "tool" to clear out gunk/debris from this gap around the edge of the screen. Some people even have used like the opposite end of a sewing needle (not the pointed end).
Many ppl have fixed a non-working screen simply by cleaning out this tiny edge gunk. Give that a shot as a first step. If you use care, you won't damage anything.

1.Check the device's battery level for at least two bars of strength.
2.If the battery level is low, charge the battery.
3.If the issue is not resolved, remove the back cover.
4.Remove the battery.
5.Wait 10 seconds.
6.Press and hold the W key.
7.While pressing down the W key, re-insert the battery.
•The device restarts and after approximately 15 seconds, the 'Recovery' screen appears
•Release the power button but *continue holding the home button*, for another 30 seconds.
Step
Thanks

@ raychel jst call yo network provider they will give it u.

ALL U NEED TO DO IS TAKE IT TO A NEARBY SAMSUNG REPAIR CENTRE SO AS TO GET IT CHANGED

Steps to Restore Phone

This will return phone to the default settings and permanently erase all user data, including pictures,videos, music, messages, contacts and downloaded applications stored on the phone.

1. From a Home screen, touch Menu ? Settings & Tools ? Phone Settings ? Security. Enter the lock code when prompted. The default lock code is the last four digits of your telephone number.
2. Touch 5 or Restore Phone.
3. At the prompt, touch Yes to reset and restore default settings, or No to return to the Security menu.

http://www.resetcellphone.com/how_to_reset_Samsung_sch-u820-reality

OK..your touch screen was jammed or not working and you did reset via code *2767*3855# then the phone restarted with the calibration cross....you tapped the cross but nothing is happening.......what to do? first shutdown the phone remove the battery for 30 sec also remove the simcard put the battery again start the phone when the calibration screen pops up tap on the cross here you must feel the tapping is working by feeling a light vibration of the phone.....then tap on the lower bar of the screen which has color (light gray) different than the calibration screen the cross will move to another corner......repeat this for all four corners then you should see and OK on the bar to save and exit to the normal screen........done

hey mate, same problem with my phone, only has happened to me recently. seems to be a problem with these phones, have you found a solution? if so, could you contact me? cheers.

not possible at all

Have you tried removing the battery and waiting for a minute and replacing it in the phone.
The phone will reboot and possibly your screen will work again.

the only solution i have found...replace the phone