video issues

[10 man]

ok here is my problem. i just got a new Gigabyte GA-K8NE mobo and i got an evga eGeForce 7600 gt ko. when i got to boot up my pc the screen goes all shitty on me. it gets a bunch of squares and lines on it and i cant really read the screen. i was thinking the problem could have been the power suply so i replaced it with a 550 wat power box. the problem still occures. im pretty sure i dont have an onboard video device with the mobo so i dont know how to hook up the pc directly to the mobo without using the video card so i can test it and set up my bios. im not sure if the video card is bad or what. its brand new and all. well now im out a PC and i have to do work on it for class. i dont have any of my programs on my mac .. can anyone help with anything?

thanks