Hey there Summoner,
It looks like since you just installed Windows 7, your drivers were wiped and replaced with a standard VGA driver. This is fine for running the GUI in your operating system, but this prevents your computer from actually using your video card to its fullest potential. This is a problem when you're trying to play a PC game.
It looks like your DirectX Tool is reporting an Nvidia chip, so I recommend using the Automatic Driver Detection tool here: http://www.geforce.com/drivers It should find the appropriate video driver for your system; if it cannot find a compatible one, please feel free to contact us through our Support Site here: http://support.leagueoflegends.com/
We'll try to help you as soon as possible; be sure to tell us what you've tried to resolve this issue so we don't have you do the same thing over again.