Frequently, spyware/adware/trojans are being "used" and "locked" when in "normal" Windows. As a result they can't be removed at that time. Try restarting the computer into "Safe Mode", then running Norton, or and other spyware removal tool. It should be able to delete the file while in "Safe Mode". If not, try removing the file manually.
CLICK HERE for How To Start in Safe Mode
Hope this helps.
Norton scans and reports adware but always replies "deletion failed" It keeps accumulating the number. I run Spy Sweeper which identifies the same adware but does delete them. Norton deletes other problems. How do I get rid of its adware report?