I checked the font settings in IE as noted above, but they were all the same as the "known good" systems. I also ran a "repair" on IE from Add/Remove Programs. Even after several reboots, it was no help.
It seems that I was able to finally repair it. It was one of two things I did (or a combination of both, I guess):
I found another fix somewhere else on the web that said to donwload TweakUI and run the Repair>Fonts option. That did not seem to do anything, so I tried replacing several .TTF font files. I copied them from a "known good" system to a network folder and after deleting their counterparts on the "naughty" system, used the Install Fonts option to reinstall from the network location. Again, that seemed to have no effect but after a reboot, all was well.
So there you go... Hopefully it will work for you - let us know!