Microsoft Tech Support Phone Scam
Scammers pretending to be Microsoft technicians call victims to gain access to their computers and hold their data for ransom. This Microsoft impersonation scam has been around since at least 2009 and has been run on computer users to extort money. Scammers will call you and identify themselves as technicians from Microsoft, then tell you that your Windows computer has a virus (or other problem) that is causing it to generate error messages on the Internet. The scammer will offer to help and have you enter a number of commands so that they can remotely work on your computer.
Microsoft will never call you to tell you something is wrong with your computer. You should dismiss as frauds any phone calls, e-mails, and online communications from anyone who claims they work for Microsoft and have detected something wrong with your computer.