Dual Monitor Issue, Nvidia 8400M GT

I have a Sony Vaio laptop, Model FZ-190e with an Nvidia 8400M GT graphics mobile graphics card.

I'm trying to plug in a Dell 1708FP monitor for an extended desktop, but it's not working. When I plug it in, the screen flashes as if it's detecting and reloading the screen, but the monitor just stays blank with the floating dell logo.


Under display settings, it only shows 1 entry:
Dell 1708 on Standard VGA Adapter

My display driver shows as Standard VGA adapter, and when I try to install the Nvidia 8M-series driver for 64bit windows 7, it starts ok and then exits the installer saying "No drivers could be located for your hardware".

Everything seems fine on my main laptop display, so the "Standard VGA adapter" works great for my single display but it will not detect my 2nd monitor.

Any help is greatly appreciated! I need my 2nd screen

here is a screenshot of the error when attempting to install the nvidia driver from the website.

someone please help...how the hell do I install Nvidia drivers? I've tried everything possible...literally everything.

I've tried this NVIDA Driver Install - Start To Finish...
and no matter what, this stupid error won't go away.

This is really starting to get frustrating. I tried deleting the driver, and it just asked to reboot and then windows automatically installed the blasted "Standard VGA adapter".

I'm starting to think Vista should have stayed on my laptop.