Delete unwanted references in the reference list

I have unwanted refernce in my reference list, and I can’t seem to delete it. I can manually delete it, but it comes back once I update my list. I am using Endnote X2, word 2007 and windows.

Thanks for any suggestions.

How are you deleting it?  You need to find and delete the citation which must exist in the manuscript somewhere.  You can’ t manually delete it from the bibliography, which is a field that will be regenerating the next time you add a reference or update the bibliography. 

thank you for your help.