Setup Symantec Anti-Virus to Update Automatically, follow instructions bellow.

Set up the Schedule for automatic virus scan

Definition updates:

1. Open Symantec AntiVirus Software. (Double-click Yellow Shield on bottom right corner of your desktop.)
2. Under File menu select Schedule Updates....
3. Once the Schedule Virus Definition Updates dialog box is open, enable Scheduled Automatic Updates
4. Click on the Schedule... button.
5. Under Frequency select "Daily"
6. Press the OK button and OK again and then Exit.