GTX 280 Driver problems

[Goose]

Hello there,
I got my GTX 280 2 days ago and haven't been able to get it working properly since. At first I couldnt find the right power supply lead but thats sorted now.
My problem now is that the drivers just don't seem to work properly or set to my screens native resolution (1680 x 1050). With the nvidia drivers everything is grainy like its on a low detail setting and I cannot get any 16:10 resolutions to work (this is with Vista 32bit btw). If I uninstall the driver and use the default windows one then everything looks great on desktop and looking at pictures or videos, but its laggy and I cant play games.
I have tried both the nvidia website drivers and the ones that came in the box with it and they give the same grainy, bad resolution result.
Could it be that my power supply isn't high enough? It's a Corsair 520HX modular and I have heard people using it with a GTX280 with no problems before but it's all I could think of. Oh yeh, and my old graphics card was a Nvidia 8800 GTS 320MB if thats anything to do with it.

E6600@3.0Ghz
2GB DDR6400 RAM
Nvidia GTX 280
Corsair HX 520W
2 x SATA HDD's 1.1TB

Any help would be very very very much appreciated!

Thanks for ready
Goose

[Goose]

Are there any alternative drivers that I could try?