... and your computer was reported to be spewing malware like a broken sewer pipe? That would mean the fake PC tech scam. See this thread:
Here's the verdict straight from Microsoft:
Avoid tech support phone scams
Strange call pretending to be from Microsoft tech support
Some relief came the first week in October 2012 as the FTC spanked whole gangs of these creeps with huge damage awards.
FTC Halts Massive Tech Support Scams