Hi,
I have advised by friend to install Gnome on his new shiny I7 laptop and everything went well for him. However after reboot, he just has Activities menu and 3 icons (battery, volume). All of them are not responding to clicks. He cant quit either. So he got to do Alt + Ctrl + F# to go to terminal and reboot.
Can you please advise how to resolve this. If not how to make XFCE the default DE, from the terminal.
If you cannot logout from the DE, you can type in the terminal;
sudo pkill X (and type in password)
On lightDM screen click the icon next to the session name to change the default Desktop Environment.
wow. thanks.
but it seems he cant get the terminal even. he gets post installation screen and after closing that nothing.
More information would be needed to figure out the issue.
thanks again lucidae, my friend is not much of an expert. will try to get this done and let you know.
Are you sure, he is a friend of yours? 
Scnr
what exactly is missing? may simply GNOME interface misunderstanding?
pressing winkey and type name of app is the way it works ?
Could also be Wayland? Did you try login in xorg, as mentioned above this can be selected at the login screen
Or alternatively lts vs current kernel if it is hardware driver related.
I had that suspicion but seems the manual partition and installation did not go very well.
He selected automatic login and hence did not have the choice of selection.
A second installation automatic partition went through without any issues and he was able to use Gnome without any problem.
However, since he want 4 partitions (3 for some other purpose), a third installation (with manual partitioning) was attempted and everything went well.
Thank you all amazing guys for the support. 