You don't need to worry about teh BIOS, leaving it at default for now is good. First you need to install windows 7. Then once that is done, instead of using the CD that came with the motherboard, go and download the drivers form here:http://downloadcenter.intel.com/SearchResult.aspx?lang=eng&ProductFamily=Desktop+Boards&ProductLine=Intel%C2%AE+5+Series+Chipset+Boards&ProductProduct=Intel%C2%AE+Desktop+Board+DH55HC
The reason being is that they will be more up to date. Remember to install teh drivers in this order: chipset, audio, video, lan, then anything else.