Win32 Vundo Removal

My Avast antivirus popped up today saying i have A dropper which is also known as a vundo? Its called this ‘Win32:VunDrop [Drp]‘. Ive tryed to delete move, move to chest ect but that doesnt work. Can any1 tell me how to remove it please. A step to step guide would be great if anybody could do that

it turns that each grid with the protection of windows he coms back when I leave my PC on the move. Ive searched the and every where but I think on a new virus.