Persistent Malware popup + possible malware file names

I am seeing a persistent popup window saying " "MTSUpdater" will damage your computer. this file was downloaded on an unknown date. ". the options below changed from "move to trash" and "cancel" to "OK" and "show in finder". neither option does anything and the window pops up again a second later. I read on one of the pages here to look in three places within the library, take screenshots, and post here for help identifying the files that may be malware. pls help.