Ok, I'm not expecting there to be an easy way to do this.
But I had a perfect working order Hackintosh (10.5.6 iPC) running on;

Asus M2N68-AM SE2 Motherboard
AMD Athlon X2 2.5GHz Processor
Zotac 9500GT 1024MB Graphics

I was using this fine for about 3 weeks, until I noticed the graphics card was playing up slightly in some programs (iMovie, even lagging YouTube videos!)

The graphics card just required an EFI String to work and support QuartzExtreme and detect all 1024MB of VRAM. But, I wasn't happy with the performance so stupidly installed the NVIDIA Driver for Mac, which has now caused my system to not boot (loading spinner gets stuck).

I was wondering if there is at all a way, whether that be using the iPC DVD or something, that I can access the files on the hard drive and back them up (my music, photos etc being the most important) before performing a fresh install of Leopard?

I'm aware this might be impossible but any solutions will be helpful!