This is windows security centre file, it alerts/notifies
The time period after which WSC considers definitions files to be out of date.
Whether WSC displays antivirus alerts for Symantec products on the host computer
http://www.symantec.com/business/support/index?page=content&id=TECH165067
Note the article which is shared above mentions about liveupdate removal ie from c:\ drive symantec \sep folders liveupdate
also from c:\users\ or documents and setting\all user\appdata\symantec
c:\program files\common files\symantec\sep