Upgraded Windows 10 to 1709 upgrade. When it had finished Thunderbird was not on the desktop but an update icon was there. Clicked on it and it said "Your computer must be restarted to complete a previous upgrade of Thunderbird. Do you want to re-boot now" Restarting does nothing and you get the same icon and message. Tried removing program from PC but get the same message Tried re-installing new version of Thunderbird and get the same message.