For Norton Users...
The 'Auto-Update' feature does not always install ALL of the updates for you.
Quite often it does not include updates and upgrades in regards to the software...
Also, the 'Auto-Update' does not always occur as frequently as new 'definitions' are made available...
To 'manually' update your definitions and program files, click
Here
These days it is highly advisable to check this site very regularly !
If you have any doubts as to which of the update files to select, choose the 'lower' and 'larger' one... Usually about 7MB or more.
Additionally, it is advisable to 'Open' the file on download instead of 'Save'.
(This is one of the very rare occasions when 'Open' is both preferable and safe.)