So I must have spoke too soon. After installing both of those (I thought I already had installed GECK Extender but apparently not, and I didn't have the most recent version of xNVSE), the GECK now prompts me to choose which files to load, which it didn't previously. But after selecting FalloutNV.esm and clicking OK, the same problem persists. Only the Render Window loads, along with the new Message Log that I presume comes from GECK Extender. And it does seem to have loaded, just without all of the other windows that should pop up. Here's what the Message Log says when I load FalloutNV.esm:
Garden of Eden Creation Kit
Computer Name: ************
The script function list doesn't have all the names filled in.
Create D3D9 instance...SUCCESSFUL
NiDX9Renderer::Initialize> Attempting to create rendering device
NiDX9Renderer::Create> Using D3DFMT_X8R8G8B8 backbuffer format
NiDX9Renderer::Recreate> Using D3DFMT_X8R8G8B8 backbuffer format
===========================================================
And here's what it says when I load FalloutNV.esm along with another mod, the Melee Lock-On mod for example.
Garden of Eden Creation Kit
Computer Name: ************
The script function list doesn't have all the names filled in.
Create D3D9 instance...SUCCESSFUL
NiDX9Renderer::Initialize> Attempting to create rendering device
NiDX9Renderer::Create> Using D3DFMT_X8R8G8B8 backbuffer format
NiDX9Renderer::Recreate> Using D3DFMT_X8R8G8B8 backbuffer format
===========================================================
MASTERFILE: Armor 'LockOnToken' needs to have biped slots selected in the editor.
MASTERFILE: Armor 'LockOnResetHotkeyToken' needs to have biped slots selected in the editor.
Does this all look normal? I just don't understand what's wrong.
Oh, and I also tried Windows 7 compatibility mode, still nothing.