Ubuntu forums and computerforums.com were no help...so here I am

I've installed Ubuntu Studio(Hardy), three times now, this time dual-booting with Vista. The only thing I have done in it is enable that standard repositories and enable my nvidia geforce go 7400 driver. Now, when I boot, I get the screen where the bar goes back and forth, and the screen just goes black. This has happened every single time I installed it. Xubuntu Gutsy works just fine, and Ubuntu Hardy works fine except for wifi, so it can't be my system..or at least it isn't likely.

...what have I done?
Nope, no sig here.