I was messing around with Compiz Settings Manager and result of that is that I cant see my panel bar, cant use alt+tab or start button. Is there a way to restore default Ubuntu environment? I will be grateful for your help
Try the following, open terminal and type:
But, If you can't get to the terminal cause your start buttons doesn't work you can always (this only works if you have a folder on the desktop) open the folder then go to 'computer>usr>share>applications' look for terminal inside the folder and click to open, then enter either of the above commands in the terminal.