I have my product key number how do i reinstall norton 360

Please download the software from the following URL:- http://www.symantec.com/redirects/norton/norton_com/n360/
and follow the screen

hope this helps.

Use this removal tool from norton to uninstall the previous norton that is installed in your system because of you dont uninstall the previous norton there will be an error when you try to reisntall the norton again

http://service1.symantec.com/SUPPORT/tsgeninfo.nsf/docid/2007080716223439?Open&docid=2005033108162039&nsf=tsgeninfo.nsf&view=docid

If you have registered your norton product, you can reinstall it any time,after uninstalling the previous one either using removal tool or directly from control panel.Once you have uninstalled the older version, u can reinstall it easily, since you have already activated your license.