A friend of mine has been getting emails for two weeks, threatening to lock his computer up if he doesn't pay them in Bitcoin. He sees the first two lines and doesn't open them, just deletes them. He seems to have a fairly complete and up-to-date suite of tools on his PC laptop to prevent any intrusions: anti-malware, virus detection and the like. He only uses it at home or relatives, not at airports or cafe's or anything. Performance seems normal and he's not experienced any performance degradation, popups etc. I've suggested this is probably just a type of ransom and he's probably fine. But am I missing anything? Couple years ago one acquaintance did manage to get his system locked up, and paid the ransom. I've suggested he get a back up hard drive and copy files at least monthly, in case of a hard drive failure or the like. If the system is already penetrated that might not help, but going forward he'd have the data from an older backup.