Ian,
When you say to click on Update Driver, click on what? On the STM Bootloader entry in Device Manager? I did that as Mike Millen suggested below. Then I went to the drivers section of the DfuSe Demo driver subdirectory, selected the proper driver directory and Windows came back with "Windows has determined that you already have the latest driver installed".
Could you please give me a more detailed step by step?
Thanks in advance,
Michael