You won't be able to install the driver without installing Linux. It may even be possible that the live system lacks a few files that are needed for setting up the correct resolutions, so that the mere act of installing to a HDD solves your problems. Wouldn't be the first time something like that happened.

Yes, I had a suspicion that was the case. Perhaps I'll try another installation. Thanks, Tobi!

I have 2 internal hard drives... the primary housing XP, the secondary used only to store images of the primary, since I'm no stranger to techno-disaster.
Last time I partitioned the primary & installed Zorin on one of them, leaving my secondary to store images of my now-partitioned primary. Seemed to work OK (other than the screen res issue), which is why I'd like to try something else this time.
Just to complicate matters, I was thinking about installing Zorin on the secondary drive. Would this be more complicated & prone to catastrophe & would it interfere with my current backup scheme? Long as it doesn't cause my motherboard to burst into flames, I'm willing to have a go at it.

I've been having a similar problem with a Dell 4550 P4 machine.