Can I use built-in LCD scaling with fixed aspect ratio?

I noticed when I played Baldur’s Gate on my 17 inch LCD monitor that using my display’s Built-in Scaling from Nvidia Control panel makes the screen a lot less blurry/crappy than using Nvidia-Scaling. The only problem is that it doesn’t maintain aspect ratio, and there’s no option to make it do so. So everything is slightly stretched vertically. Is there a way to use display’s built-in scaling but while maintaining aspect ratio? I’m using a geforce 8800GTS w/ 258.96 drivers and a BENQ FP93GX monitor, if that means anything.