
This means that I can remotely access that PC at any time without their intervention.

I have this setup for only one computer and my parents are aware of and approve this configuration. The third install is a full client install, but with a permanent pin added. There is no way for me to access their computer without the pin that is generated at the time of access. In both of these cases, they need to give me a computer ID and PIN that is generated uniquely for their computer. This way they don't have to download it each time they want help. For others that I help regularly - I have them install the full client. When the program exits, there are no traces left behind. People that I help rarely can use the instant installer - it downloads and runs without anything being installed. They have three modes and I used all, depending on the user. With Team Viewer, I am able to help my family by remotely viewing their computers. It is hard enough to get Microsoft to call our company back when we use paid for Premium Support packages, let alone them calling an individual user.

Microsoft will NEVER call you personally about a problem with your machine. Your phone call WAS NOT a legitimate purpose! As others have stated, it is a SCAM, you may already have a virus (scan for it with multiple tools - your Antivirus also, MalwareBytes, and other "instant" antivirus scanners.

I have used TeamViewer for years - don't let this experience keep you from using Team Viewer for legitimate purposes.
