There’s a bad virus/worm known as Conficker or Downadup which may have infected your PC. Go here to read about it and what it can do to your computer if it is infected. There are several free downloadable removal tools available. I used this one by Bitdefender which has versions to clean a single pc or a network of linked computers. You can find others here and here (and probably other places as well. So far as I know this doesn’t effect Macs, only computers that use Microsoft operating systems. So please, if you have a PC download one of the free removal tools and run a scan to find out if your computer is infected and to remove that infection.
Don’t wait on this one.
