The first inkling of a trojan in my PC was when AVG reported one in a HP (printer) file.
Just ocurred to me - the HP software installs to default keeping a com port open to report problems, pick up software updates etc. Could this be why the trojan installed to the HP printer files ?
I've just gone to the HP settings and turned everything off everything associated with automatic up and down linking of info., just wondering whether this will be enough.