Thank you Jackcoms for your reply! I forgot to mention that the NVIDIA message ends with NOT REPSONDING. Does this make any difference to your advice given and do you know why I'm getting the message in the first place? Thanks again!
I have one machine where this message appears sometimes on shutdown. I did try and get rid of it but nothing seemed to do anything. I then thought that there are other, more pressing, things to worry about so I ignore it now.