I mistakenly changedthe setting, From that time my status symbol is not appearing in the taskbar.. please guide me to correct it.

Satish,

Your question doesn't give much detail, so I'm making some big assumptions here. If you are running Ubuntu Linux, and if by "taskbar" you mean
the menu bar at the top of the screen, my suggestions will help you correct your error. If these assumptions are not correct, please send more info.

If you right-click on a blank part of your top menu, a menu will appear. The top item says, "Add to Panel". Click on that, and a window will appear,
with optional items you can add to the menu. Click on the item you want, and you can drag it into the menu and place it where you want it to appear.
If you right-click on that icon, a menu will appear that lets you do various things to that item. If you want to move it, there is a menu item for that.
Once you have it where you want it, the last menu item lets you lock it where it is. If you want to move it again, you will have to unlock it first.
I don't know exactly what you mean by "the status icon", but it should be in the big list that appears. I hope this helps you. :-)

Jerry