I recently bought and installed Norton with back up to replace my older 360. On my windows 7 PC it runs for a few days and then refuses to open on the desktop for me to perform scans etc. I have installed it on my other pc running windows 8 and it is fine. I have asked Norton support for help but they appear not to be able to. On my Windows 7 PC I have removed and reinstalled the programme several times. It works fine for a few days and then reverts to not opening. Has anyone else had this problem?