And BTW, if you have to deal with somebody who download spyware crap but is clueless, here's a good technique:

People have some important data on their computers, and clueless people never have any backup.

Just pretend for 10 minutes that their data was wiped. Appear to try VERY hard to recover it. Once it is recovered, explain why they shouldn't download any of this shit - you can be sure they'll listen then.

It's not nice, but it makes the threat real enough for them.