on you nav warning dialog box click on the link which will be the name of the virus. this will take you to the nav web page for this virus. then goto control panel/system/remove system restore tick for system restore,click on the highlighted word tool back ion the web page and run the tool.
this should clear the virus.
run the tool a second time to confirm it has gone empty recycle bin and norton bin then reboot and put the tick back in system restore.
the latest version of this worm is not stopped by the xp update I found to my cost.