1. Go to Excel Options (that's the circle in the top left corner of the screen, then bottom right of the dropdown)
2. Go to "Trust Center" and click on the button called "Trust Center Settings"
3. Select "Disable all Macros with Notification" and click "OK"
(This will remain as the default setting for Excel)
4. Close the your file and then re-open it
(When the file is re-opened, a security notification will appear above the edit line)
5. Click on the notification "options" and choose "Enable this Content" and click "OK"
(Stage 5 will need to be repeated each time a macro enabled file is opened)
The warning is not as "in ya face" as version 2003, you just have to get used to it