gerbil,
Thanks for the suggestions. I've not tried any of them, but I may yet depending on how things go here.
Some helpful souls at my place of employment convinced me to switch to FireFox, thinking that it wouldn't be susceptible to the issues I'm having with Internet Explorer. I had high hopes, but after installing it from a flash drive, I get pretty much the same results as I do from IE, just with different graphics/icons and slightly different wording.
Anyway, I downloaded ATF-Cleaner, Malwarebytes' Anti-Malware, and HijackThis to that same flash drive at work, and am now able to at least run some of the suggested cleanup.
Thanks,
Pete