Hi mark, first I can tell you that the virus reports are safe to ignore, we are asked about this anoyance all the time, windows will report any new or unknown program the same way, so you will hat to tell your antivirus to ignore it.
ok, as for your genres, it sounds like your tracks may have been previously tagged with 2 or more genres, I think an easy way to check is to right-click on a track and look at its properties, it may show you what genres the track has.
You can also tag genres directly form within Home Jukebox menu (to enter menu press TAB key on your keyboard).