Just a 'heads-up' in case you have the same problem. We subscribe to Malwarebytes Premium on our two laptops which gives real-time protection. This morning I noticed that the icon had disappeared from the desktop and found that there was no trace of the programme on either laptop. We've downloaded it again and input the activation key with no problems but how did the programme uninstall itself? Just running a scan to see if there are any nasties lurking.