Hello I was just browsing on Firefox this afternoon and my screen locked and a message appeared that told me I had something wrong with my hard drive and to call a certain number or my hard drive would be deleted in five minutes. Like I said the screen was locked and the message looked very basic, like something that looked like a command prompt texts. There was also an audible voice that said this as well and a five minute timer. I tried to close it then I figured my best action would be to reboot my computer before the timer ran down. I just updated my Windows 10 last Tuesday and I have a custom built Gigabyte GA-Z170X-Gaming 7 with an Intel I7 sky-lake. I have run a full system scan with Norton and run Norton Power eraser as well. I do not know if this might be a virus or I read it might just be a bad add on in Firefox. I am really concerned that this might happen again and hope this is solved soon and does not effect my other computers. I had also just installed a Linux virtual machine for school about thirty minutes before this happened.