Well, it appears I was wrong about the cause of my Microsoft Trackball Explorer (an original v1) problems. It's not the driver. It's the hardware. And as Spock would say, "It's dead."
So, for the time being (meaning today), I am using one of the Logitech Trackman Wheels floating around (I'm stealing it from my laptop carryall). It's letting me get by. I'm irked at it's constant desire to middle-click AND click on one depress of the scroll wheel. That tends to NOT be what I want. But being less quick on the trigger has left me with some control of the device.
I looked on the internet to see what my options were and folks, they are grim. Really, the only track device with a big finger ball and a scroll wheel leaves with one and only one choice. The Logitech Cordless Optical Trackman. I don't necessarily want a cordless device, this NOT being a mouse and all, but c'est la vie. I can buy it around the corner at Staples for 80 bucks, or detour to Tiger Direct on my next visit to my main client and save 20 bucks. After a day of working with the thumb marble type Trackman Wheel, I'll know if I have the stamina/patience to save the 20 bucks.
I've used the Explorer for four years as my main machine's pointing device. Before that, I was pretty well a Logitech trackball user. I had several and quite liked all that let me move the ball with my fingers, rather than my thumb. I still have an old Logitech trackball on my reading computer. But it doesn't have a scroll wheel and using anything without a scroll wheel on the internet is just plain too much work.
Whatever happens, it's going to a strange day using my right fingers for the the left and right buttons after all these years using my thumb!