I am running Windows 8.1 at the moment. I purchased and downloaded Norton 360 on 7-31, it failed. I didn't realize it wouldn't remove an older version, so I ran Norton Removal tool. Seemed to work and I was able to download new version. However, Norton will not open when I double-click the icon. I see others are having a great deal of trouble with Windows 10, I haven't upgraded to it yet. What do I do?