Screen pixalating only with driver installation on brand new computer

I just put together a new Gigabyte 2004 rz series mobo with an athalon 3000+ xp processor and a Xfx geforce 6600gt vid card. Got a gig of ram and started up perfectly first try. Problem is when i load the drivers for the video card, the screen looks like your psp when you threw it at a wall and some of the crystals died in the display. Pixels are missin on the screen and opening new windows just makes it worse. I unihnstalled the drivers and the screen looked crystal clear again. Being that i built the computer for World of Warcraft, i kinda need those drivers to be in place for it to work properly :/ please offer any advice you might have, thanks.

Are all system drivers installed?
Have dx9c installed?

installed the CD that came with the mobo, and also dx9 that was on the disc with the vid card drivers

In device manager, does it show any problem devices?

i havent checked there yet, will do once i cant get to the computer, she went on vacation fight after i built it and havent been able to look at it since, 2 more days and i can get to it :/