My top right hand corner bars gone log off ,on ,restart, volume, more cant log off computer nothing

The back has gone out???? Do you mean the back button icon on the display? The one that looks like this: < ???

If that's it, try a Restart. You can do a Restart by touching the settings icon (right hand upper corner - three bars) and then
touch Settings. When the Settings screen comes up, touch the Settings icon in the upper RH corner again. A drop down menu will appear and Restart will be one of the options. Touch it and let it do its thing.. Be careful to touch Restart and not Reset which is right below it.

In the top right hand corner there is a drop down arrow, click this and 'log out' is the fourth option down

Reboot your computer, OPEN YOUR CHROME WEB BROWSER, AT THE TOP RIGHT HAND CORNER CLICK THE THREE BARS, SCROLL DOWN TO SIGNED IN AS CLICK ON IT, SCROLL DOWN TO USER, SIGN IN AS ''NEW USER'', CLOSE BROWSER..OPEN FACEBOOK AND LOGIN...

ubuntu upgrade it now my tool bars gone log on, log off, restart ,volume control,sign in all gone cant log off restart nothing my numbers on side key board not working it was til upgraded i done everything i know to do to correct this not working

use a different browser. it may be the browser. if that doesn't work, then use live to chat on fb! it still will do that! or use tinychat!

While riding, tap a corner of the status bar

1. Horizontal status bar on the left corner where is shows the directional arrows
2. Vertical status bar: On the top corner, where directional arrow are shown

After you tap the correct corner of the status bar, a volume slider appears at the bottom of screen. Move slider to the right to increase volume, or to the left to decrease volume.

While riding, tap a corner of the status bar

1. Horizontal status bar on the left corner where is shows the directional arrows
2. Vertical status bar: On the top corner, where directional arrow are shown

After you tap the correct corner of the status bar, a volume slider appears at the bottom of screen. Move slider to the right to increase volume, or to the left to decrease volume.

Make sure that the audio cable from the computer is in the correct audio output (small green socket) and connected into the monitor. You can test the monitor speakers with an MP3 player or a smartphone. Also check that the volume on the monitor is up.

Menu....display ...off
this should do it