If someone rings you up and claims that your "inf" dir is full of "infected" files.... hang up

There is a scammer on the loose hoping to get into your PC by claiming that your INF files are by default "infected". They are turning what are usually harmless and necessary information files into some sort of "proof" that your PC needs help. Don't believe 'em. Just hang up and run your virus scanner on that folder to prove it to yourself. 

INF file - Wikipedia, the free encyclopedia

An INF file (stands for information) or Setup Information file, is a plain text file used by Microsoft Windows for installation of software and drivers. INF files are most commonly used for installing device drivers for hardware components. Windows includes IExpress.exe for the creation of INF-based installations. INF files are part of the Windows Setup API.