Resolution stuck at 1024x768 nVidia Geforce 9500 GT

I've installed Snow Leopard 10.6.6i by hazard and it was successful , but I'm having a problem with the resolution ,It won't go higher than 1024x768 ,I've installed the graphic kext that came with the DVD and when I try to increase the resolution I get a blue screen ,any one can help please ?
Gigabyte EP45-UD3L
Core2 Duo 2.93
8 GB DDR2
Gigabyte nVidia geforce 9500 GT 1 GB

I've installed Snow Leopard 10.6.6i by hazard and it was successful.
The differences between You and I are Gigabyte EP45-UD3LR and Asus nVidia geforce 9500 GT 1 GB.

I am also new on mac butt try this

go to Preferences>Display>change ur setting as u want make sure that your moniter/Lcd support that resolution and then chane the resolution if screen goes blue then sipmly press(enter) and after that press...(windowskey+shift+q)and press enter
it will surely work as it worked for me......