You can go into the BIOS by pressing a button BEFORE Windows starts. But the details of the buton to press only displays for a second or 2 before going off the screen (each PC uses a different button).
It may say "press DEL to enter SETUP (or maybe BIOS).
But to be honest if you dont know your way around the BIOS be careful because there are some important options in there which you cannot afford to change.
Also, if you are doing an install of Windows have you got all the drivers for your sound, graphics, networking etc, because without them some of your components will not work.
I hope you know what you are doing, good luck.