“Hello, this is the Microsoft Technical Windows Department. We have just seen that your computer has a serious problem that is affecting the Internet”.  Even if you haven't yet had this type of call, it is likely that, with random dialing systems that the criminals use, “Microsoft” will call you with some bogus story about your computer..

Microsoft will NEVER ring you directly as they do not have any details about you.

DO NOT follow any instructions.  Simply put the phone down.  Usually the criminals will ask you to enter something into your computer.  This will lead to remote control software being installed. Once the software has been installed the criminals can take over your computer without your knowledge. You may be asked to pay for the 'work' that they've done. The sum involved can be significant.

Highway has had computers where the owner has followed the procedure and allowed the bogus company to gain access to their computer. The problem is that it is not known what was installed on the computer, and the only way to be certain that nothing is left is to completely rebuild the computer. A lengthy process!