Laptop Fraud Alive and Well

I fired up my laptop computer Sunday morning and quickly lost everything on my desktop.
Wow.......met by a shrill beeping sound and a warning about shutting it down. Everything would be lost and sure enough, my total desktop immediately disappeared from the screen. Calling the listed 800 number for help was fruitless.
Calling a friend -- a computer professional -- it was confirmed that this had not been a warning allegedly from Apple/Microsoft firms. He told me to hold the power key down for 15 seconds and everything would probably come back on my screen.
It worked and I was back in business. It had definitely been a fraud contact. Others who might not have the value of my computer contact and turned off by the screeching warning sounds might have given their private information to the caller.