The machine was pretty slow already. However I decided to execute sudo apt-get update.
However the update stopped at 90% updating some trigger.
So I decided to log out and re login with user. However the system didn't let me log on any more.
So I decided to log on with an alternative user and triggered the update again, same message:
Unable to lock the administration directory (/var/lib/dpkg/) is another process using it?
Then I tried a shutdown. Now I just see the Ubuntu logo and white/red dots moving from left to right.
This machine is important for me, what's the best thing to do for me now?
Should I just switch off power and reboot?
Your help is very much appreciated!