You apparently didn't run the Norton Removal Tool. Enough Norton junk is still on your computer that Windows Defender didn't know it needed to turn back on. Run the Removal Tool and the rest of the Norton junk will be deleted - no need to reinstall and start over.I had this problem when Norton expired. I removed all Norton products, ran Ccleaner, rebooted, Then I was able to start Defender.
Are you looking for the solution to your computer problem? Join our site today to ask your question. This site is completely free -- paid for by advertisers and donations.
If you're not already familiar with forums, watch our Welcome Guide to get started.
Join over 807,865 other people just like you!