I'm going to assume, since this is your first post, that when you say "downloaded" you mean "installed a legal, licensed copy of Windows" under Boot Camp. We don't support piracy on this forum.
With that intro, welcome to the forum! Please read the two stickies at the top of this forum as they will answer almost all of your questions about Windows under Boot Camp. You didn't indicate the version of OSX you are using or the version of Windows you installed. Again, the following assumes Snow Leopard and Windows 7. To get all the drivers correct, boot into Windows and then insert your Snow Leopard install disk - it should auto-install all your Windows drivers. Then download and install (again, from within Windows) the latest version of Boot Camp (3.2) - either manually from the Apple download site (be careful to pick the 32-bit or 64-bit version that corresponds to the version of windows 7 you installed), or by clicking on the Boot Camp icon in the Windows system tray and running the software update there.
Good luck and again, welcome to the forum!
Cheers