Kill Finder pop-up window for LiveUpdate "ALERT: Please contact the Service Desk at [phone]."?

Question

Hello! I bought a second-hand 2008 Intel iMac last May from Ebay, which I was told was wiped but was/is not entirely. First off I will say I'm not a programmer; secondly I will say I first had Snow Leopard on this system and have recently upgraded to Mavericks, and the problem remains.
I started receiving the occassional popup window on my desktop: "ALERT: Please contact the Service Desk at [phone]. Your AntiVirus software needs repair. LiveUpdate could not be found in the expected location." Typically appears after every time I restart my computer. I don't have LiveUpdate installed, so I did some Web searching and found that Symantec installs can sometimes leave crumbs around your computer, so I did some Terminal window stuff to try to clean this up (can't remember exactly what I did, but it was instructions from the Symantec website for uninstalling LiveUpdate). Didn't stop the the windows from popping up. I left it for a while, then was aggravated again when I found some parental settings in iTunes set by what seemed like a ghost administrator that was not there -- searched on that, and resolved the parental settings issue by clearing all relevant settings and fields under System Preferences > Network > Advanced, through which the computer was once remotely administered by TimeInc.
I thought that would also take care of the popups as well but it didn't. I did the Symantec uninstall (that I mentioned above) again, no luck. I had been trying to search the Web for the entire popup message text to no avail, but then I tried just searching for the first sentence, and I found a website where someone had written code that looks to be for sysadmins to make these messages appear on computers they administer. I am almost positive my computer is not being remotely administered, but I assume I need to do something in my Terminal window to make this message stop appearing. Here's the code I found on the Web:
if [ -f "/Applications/Symantec Solutions/LiveUpdate.app/Contents/MacOS/Liveupdate" ]
then
$logger "LiveUpdating Silently"
"/Applications/Symantec Solutions/LiveUpdate.app/Contents/MacOS/LiveUpdate" -liveupdateautoquit YES -update LUal -liveupdatequiet YES
$logger "LiveUpdating Completed"
else
$logger "LiveUpdate is missing!"
osascript -e 'tell app "Finder" to activate' -e 'tell app "Finder" to display dialog "ALERT: Please contact the Service Desk at [phone]. Your AntiVirus software needs repair. LiveUpdate could not be found in the expected location."'
fi
$logger "Terminating Normally"
exit 0
Any advice on how to kill this Finder pop-up window will have my eternal gratefulness. Thanks!
- Justin

Answer 1

My preference is to not reinstall from scratch.
Well, I can't in good conscience help with that. Essentially, what you're asking is the same as a guy telling his doctor, "Sorry, doc, I'm going to keep right on eating a dozen doughnuts a day, I just want you to give me a pill I can take to keep my arteries clear."
Not only might there be malware on the machine, either accidentally (no, Symantec products won't do a decent job of protecting against that) or purposefully installed by the seller, but the machine obviously contains all manner of software that you do not have a license for. That software should not have been left on the machine, and it is not legal for you to be using it.
Save yourself a lot of trouble and just wipe it clean. You'll get a fresh system, with no residual issues and no legal problems to deal with.