"Mr Codger, this is Nabil from Microsoft and it's come to our attention that your computer is infected with malware."
"Really?"
"Yes sir, and we can resolve the issue for you now"
"You must have a very high level of expertise to be able to do that."
"Yes Mr Codger, I have blahbity blahbity certification"
"I wasn't aware that Microsoft has a time travel division"
" long pause... I can repair the problem with your computer quite easily"
" I'm very impressed since I have't purchased a computer yet but you are going to repair a problem on a computer that I don't even have. Can you tell me what problem it is that I'll have when I do buy a computer?"