I checked the inf file - but I see no place where I'm supposed to rename it to make it recognize my card.

My card's a NVidia Geforce GT 420M. PC is Acer Aspire 5745G.

Which driver did you download and what's the hardware string?

The ***laptopvideo2go page I linked to*** had a separate download link for a modified inf. It seems to have many hardware strings added to it, including
NVIDIA_DEV.0DF1.03 = "NVIDIA GeForce GT 420M"
Have you tried using that inf to install the driver?

People, FYI - I'm solving this problem with dual booting the Acer laptop that I bought in Feb by buying the Dell Inspiron M1530 on ebay last week, which, luckily for me, XP drivers were readily available for it as I'm going to wipe its hard drive clean of Vista and do a fresh, clean install of XP (32-bit) on it.