Thanks for all the replies. I do plan to upgrade my OS AFTER I manage to transfer my important files to my new computer.
I may also try a more advanced AGP video card on my Dell to see if I can get higher resolutions. I am not optimistic for two reasons: 1) nVidia says my current card is capable of 1600x1200 through the DVI port but it apparently is not on my system, and 2) my current card is purportedly capable of generating display resolutions up to and including 2048x1536 through the VGA port, but on my system the maximum available VGA resolution is 1600x1024 (same as through the DVI port).
If my system does not support the maximum resolutions of a G-Force FX series card, I would be surprised if the higher resolutions of more advanced cards would function on my system.