Many, many thanks to Towns and others in this thread and associated ones. I searched the Web top to bottom, spent a couple of days with this problem, before I found this site and the fix. For some reason I can't find the particular post that stepped me though the uninstall process, but thanks to whoever for that!
For me, fonts were good in some programs, not in others. Turning Clear Type on and off would toggle the bad fonts back and forth to good, and vice versa. But once I uninstalled KB3013455, all my problems disappeared. Now fonts are back to normal in all programs. By the way, Microsoft has an online Clear Type Tuner on their site that would not function for me because it saw Clear Type turned "OFF" on my machine, whether it was on or off. I downloaded some utility that was supposed to do the same thing, and was able to run it, but that didn't help. Removing the update was the only fix, and it worked just fine.
HOWEVER... no sooner did I remove the update and reboot, but there was Windows Update with a little icon in my tray. And no need to say what it wants me to install: KB3013455! No, thanks, I'll take my chances with whatever security threat it pretends to fix, just no jagged fonts, please.
If MS does come up with a patch around this problem, I wonder if it would be wise at that time to reinstall the bad-boy KB and then run the new update? We'll see. Anyhow, thanks to all for sharing the wealth; now I'm a member of the group here and maybe can keep Vista running for another 15 years!
