ubuntu won't accept password

If you press CTRL+ALT+F1 and log in there, then run:

df -h

Are the partitions for Ubuntu quite full?

 Didn't get that far. When I tried to sign in, using the correct user name and password, it came back "invalid password". FYI I have Xubuntu. When the sign in screen comes up, it says ubuntu.

Then I suggest you reboot and hold SHIFT, select recovery mode then select root. You can now run:

passwd foo; reboot

Replace foo with your username. Eg:

passwd andy; reboot

You can now log in as your username with the new password.

 Same problem.

Did you check the free space while you were changing your password?

  Never got to changing my password. After I did the ' passwd andy;reboot' thing , the thing rebooted and no change in the problem.

did you check the free space in the root recovery console?

  How do you do that?

Run:

df -h

Like I stated earlier....

said:

Filesystem Size Used Avail Use% Mounted on
/dev/loop0 17G 16G 0 100% /
none 497M 236K 497M 1% /dev
none 502M 0 502M 0% /dev/shm
none 502M 32K 501M 1% /var/ run
none 502M 0 502M 0% /var/lock
none 502M 0 502M 0% /lib/init/rw
/dev/sda1 466G 42G 424G 10% /host

Yes, your file system is full so you will have issues logging in. If you run:

uname -a

You will see the running kernel. If you run:

dpkg -l | grep linux-image | grep -v linux-image-generic

You will see the installed kernels. You can remove any of the installed kernels but not the running kernel.. This will save a lot of space. And will fix your login issue. Or you can uninstall Libreoffice and log in, then remove the old kernels and free up space by using bleachbit intelligently, then reinstall Libreoffice. Either way is fine

  What is the command to remove/uninstall Libreoffice?

sudo apt-get --purge remove libreoffice*

Said "command not found".

sudo apt-get --purge remove libreoffice-core
sudo apt-get --purge autoremove

Should do it