FF7 for the PC is a difficult beast to make run. First and foremost you'll need the TNT patch, then Quimm's Chocobo patch; you also need Application Compatibility Toolkit 3.0 or more recent (it'll need some particular settings to work).
Thing is, this game is extremely dependent upon the graphics driver: I know for a fact that any driver past version 56.72 will mess up its textures loading.
As such, your best chance is to run it in software emulation mode - don't forget to set its affinity on a single CPU if you have a multicore. Also, completely disable anti-aliasing and anisotropic filtering. You may use Rivatuner to set up a custom 2x2 antialiasing mode that will make it look much better, but that's for the time when you can actually run it.http://qhimm.com
: ultimate resource on FF for the PC.