I had a similar problem with Norton I wanted to remove all the odd remnants of Norton. I just could not get rid of everthing associated with Norton. With advice I received for PCA I downloaded regseeker. I did a search for NORTON deleted all occurences and then did a search for symantec and deleted that also. Problem solved.
Hope this solves your problem. Just make sure you tick the backup button on regseeker before you remove anything.