Usually they try to get the user to download a file which is actually aand so precisely what is the plan to check for problems?
run what? inquiring minds want to know!
virus or trojan. If he did not do that then he went unaffected. I have
had three of those calls. It's usually someone with a very thick accent.
So the answer to your question is: scan with an Anti-Virus program first
like Avast, etc., I would also suggest a quick rootkit scan as well
using TDSSKiller and then do a malware scan with MalwareBytes,
SuperAntiSpyware and perhaps Spybot Search & Destroy 2. Do quick scans
with all and if anything malicious turns up, run full scans.