I use 3D modeling applications and do a lot of graphics malarkey on my Mac Pro (early 2008 model). The other day while doing just that my Mac appeared to freeze & the display showed lots of zig zagging, dotted, coloured artifacting. I restarted the thing & it looked fine again, but after a few minutes, the same thing happened. Now I can't even boot up. It's stuck on the Apple boot screen with vertical, dotted, purple lines on the screen. Oddly, by using the function keys I can invoke iTunes & hear tracks, so the system has actually loaded, I just can't see it. I can also shut down by using the ctr-alt-cmd-eject keystroke. The graphics card is an NVIDIA GeForce 8800 GT The Mac Pro is the early 2008 model Can anyone confirm this is my graphics card before I attempt to replace it & if so, can anyone recommend any suitable replacement cards? Thanks PS, I have no apple care, warranty is out, have reset PRAM & SMC as first port of call.