Ubuntu does not boot due to disk space full

Ubuntu has started if you are able to do commands, it is just the gui you are missing. Now you just need to delete things with the rm command.

Please be careful, and make sure you understand what you are doing.

Perhaps you can delete some old logs? In the /var/log folder there are lots of logs.

Anything ending in a number such as .1, or a number with a gz suffix - .2.gz is an old log file. It is fairly safe to delete these.

However, you can use the du -shx /* command to see which of the root directories is using the most space. It is likely to be the /home/ directory, and your own home directory. Probably email or dropbox is taking up the most room.

I would personally try to boot from a live CD and try mounting /dev/sda7 that way. Once you can get it mounted, you should then go through and see what large files you can delete to free up space.

I hope this helps!