Can you download wii virtual console games from my COMPUTER to and sd card the transfer it onto my Wii

You cannot do this, because VC games are unique to each console, so they will only play on the console on which they are downloaded.
Actually, if you have a Soft-Modded Wii, you CAN use NUS Downloader and a WAD manager to do exactly just that, but if you have no idea what you are doing, you will end up destroying your Wii and making it completely unusable. Also its illegal.