Hello yurtgirl, ive popped in a nicotine lozenge and my paranioa had gone now Sometimes things like your describing get downloaded onto your pc with a thingy that reawakens them everytime you switch the pc on, so you have to manually remove the bits.
If you google what ever the thing is like "wormitus shopper" you should get up sites telling you how to remove it.
Thats for future reference, hope your pcs ok now!