Norton, in my opinion, is the worst antivirus out there. If you want some good protection that is free and LEGAL, follow these three links to download.com for some good free security software.
If you decide to follow this, use this configuration for antivir for best results.
This is to setup antivir after it has been installed.
Right click on the logo in the taskbar(a red square with a white umbrella), then left click configure. Towards the top left, you will see a box beside expert mode. Check this box. Now click the + beside scanner, and now the + beside scan. This will expand them.
Now click on scan itself to where it is highlighted. Now to the right under files, select the circle beside all files. Now click on action for concerning files. To the right, click the circle beside automatic. Now to the right of that, set primary action to repair and secondary action to delete. DO NOT check the box that says "copy file to quarantine before action".
Now click on archives to where it is highlighted. Make sure all boxes on this page are checked, if not check them. Now click on heuristic. To the right under win32 file heuristic, check the box beside "win32 file heurisitic", then click the circle beside medium detection level.
Now click the + beside guard and the + beside scan to expand them. Now click on scan to where it is highlighted. To the right under scan mode, check "scan when reading and writing". To the right of that under files, click the circle beside "all files".
Now click on heuristic to where it is highlighted. Check the box beside win32 file heuristic, and then click the circle beside medium detecion level. Now click ok and antivir is now setup for scanning.