My Samsung notebook n150 display unable to display "cinnamon-session-cinnamon" not found; falling back to default session
 

I have just updated my mint 18.1
I have pressed control alt F1 but I can not remember my password to log in.

Gastoneciacci,

Welcome to LQ.

Boot from your USB installation drive as follows:
http://www.psychocats.net/ubuntu/resetpassword

In any event I would be inclined to copy and paste all personal data to an external drive and then use either the lighter MATE or Xfce version of Linux Mint 18.3, as opposed to Cinnamon.

Better still, since this is a netbook, it would be better to use something truly lightweight such as antiX:

https://antixlinux.com/