Man with heavy South Asian accent claiming to be David Johnson calling from Windows Technical Department. Said there is a problem in my computer, that it is infected with a software bot. Wanted me to perform a number of operations in the guts of the computer, none of which I did. I finally got tired of him and said he was a scammer trying to harm me and my computer. He denied all of that, and insisted he was only trying to help. This is a dangerous scam. Don't fall for it.
As if a company would call to fix a problem you didn't report...especially when a third party (virus) is the culprit.
Your ISP will notify you via email for example, should your IP address be suspected of malicious outbound behavior on their network. Its not common sense...its just sense and its seemingly uncommon enough to propogate these ppls existences.