I am confused by what your BIOS guide says about these settings. Your explanation says to use either "OS" or "BIOS" for the USB Mouse and Keyboard settings in the BIOS and that if the "BIOS" setting is selected, only rudimentary functions will be in Windows for the USB mouse and keyboard. In the DFI BIOS, there is no "OS" and "BIOS" option, there is only "Enabled" or "Disabled". I don't know what you mean by only having rudimentary functions in Windows if choosing the "BIOS" option cause I'm using a USB mouse and keyboard and have the options "Enabled" in the DFI BIOS (which I assume is the same as your "BIOS" option) and do not think I have any functions limited in Windows. Here is another explanation I saw in a forum when this was being discussed (pertaining to your BIOS guide explanation of this). This makes sense. I would like to know which one of these explanations is correct because they are quite different and there are an awful lot of people out there using USB mouse/keyboard that have these options Enabled in the BIOS.