Cannot open gnome-terminal from Unity launcher or from side panel shortcut

Solution 1:

Although we only can guess what has happened, two things seem not in order:

1. The fact that in Dash, you get nlykkei@nlykkei-Ubuntu:~, when looking for the terminal, confirms the fact that you must have a local (error-some) copy of the gnome-terminal.desktop -file. This also explains why it does run from cli in xterm; the .desktop file is surpassed then.
2. The fact that you lost colors in the terminal points to the fact that there is something wrong in your ~/.bashrc -file.

To solve

1. Remove any local copy of a .desktop file, calling gnome-terminal (to be found in ~/.local/share/applications). The Unity Launcher and Dash will then use the global one again.

2. Restore the original ~/.bashrc file by running the command:

    cp /etc/skel/.bashrc ~/
   

Subsequently log out and back in, and it should be fixed.