I'm now on Windows but I have Xubuntu too.
When I restart my computer and boot into Xubuntu, the loading screen appears and when is time to show up the desktop, nothing happens, it remains on black screen.
Before an hour or two everything was fine except downloading from Internet. When I try to download something an error appears and says that I don't have enough places to download. When I go to the File system and check how many place do I have on my hard disk it says, 36 GB on local disk (second partition).
When I restarted my computer the problem with the black screen