Today I got a voice message telling me to call 1-800-642-7676 because my Microsoft Windows system needed upgrading. But, I know that Microsoft does not call the users of their operating system when an upgrade or update is available. It seems online scammers have spoofed the Microsoft number (800-642-7676) in an attempt to trick their potential victims they are calling from Microsoft.
Remember, never give access to your computer, to your bank account. Make THEM verify your information to YOU. Do not go to any website that they tell you. If you have troubles with your computer, take it to a reputable business in person, or a person you trust.
Do not trust anyone who calls you out of the blue. It's different if you requested help, but if you get a pop-up virus on your browser, exit the web page. Do not download anything from the internet or click 'yes' to pop-ups.
While this number might go to Microsoft if you call it, spoofers can mask what number they are calling from and are untraceable.