So, I installed the xubuntu-desktop package on my Lubuntu netbook, but when I went to login to a xubuntu session nothing happened. The screen simply went momentarily blank and then came up with the original login screen again.
I tried with xfce session and got the same result. I was logging in with my ordinary Lubuntu details.
I did find one thing to try, which I did, which was to reset Xauthority... Not sure what that is but it didn't help anyway.
I haven't really found anything else similar to this problem, so I thought I'd ask here if anyone else had seen or experienced a similar issue.