You MUST turn off system restore and uninstall any existing Anti-Virus software before installing Symantec Anti-Virus.
1. Click the Start Button and right-click on "Computer"
3. Click on the "System protection" link on the left menu under "Tasks".
4. In the User Account Control box, click on "Continue".
5. In the System Protection window remove the 'Tick' mark from beside the drive you want to disable system restore on.
6. A message will now appear asking: 'Are you sure you want to turn System restore off'. Click the "Turn System Restore Off" button.
8. System Restore will now be turned off permanently on that particular drive.