My Surface Pro 3 recently contracted a Virus that was pretty serious. I couldn't run most programs, especially anti-virus programs. I couldn't get the computer to boot off of a thumb drive. It was really my fault because I was running some stuff that needed AVAST anti virus to be turned off . There were a lot of sites popping up with cyrilic characters. So, I suspect that the virus was Russian in origin. Microsoft has a free virus removal service when you set up a tech appointment. They could not restore the OS to a normal condition ,even though they managed to get an anti-virus program to boot the computer. At that point, I told them to wipe the drive and re-load a fresh OS. When I picked up the computer 2 days later it was, basically, a new machine. I was very pleased with the job they did, as well as their friendliness and cooperation.