Appears to be the old "Windows Technician Scam", i.e. your computer is sending out signs that it is infected with a virus, the caller will have you log on to your computer to show you some "problems", then the caller will offer to fix your problem if you just provide him with a credit card number. Just search on some variant of Windows Technician Scam for more details. Note - 213-260-4176 is the number the caller provided, it did not register on my caller ID.