I have a hp laptop dv6799ea with NVIDIA GeForce 8400M GS but am not impress with it at all. The white on the screen display is not brilliant white as my girlfriendz msi laptop with intel graphics chip.
It is probably the brightness of your screen rather than the graphics card.
lol trust me, i ave tried all the various setting re brightness and adjusting colour settings via the Nvidia control panel, i can get it really bright but cant get it clear or brilliant white, just white wit a light brown tinge to it.
ROFL's right, it's not your Graphics card, it's your screen quality (or lack thereof). Adjusting the colors isn't going to brighten the screen, maybe try just... Increasing the brightness of the screen, if it isn't all the way up.