You think you have font rendering problems...check out what IE anc Chrome do on my PC here at work...
http://i1046.photobucket.com/albums/b467/valve90210/wiki_zps275725dd.jpg
Can't get to the bottom of it tried all sorts. Instead I just use Firefox now! lol
How...
To OP, here's something to try. Go to IE's settings, under the "Advanced" tab, tick "Use software rendering instead of GPU rendering", then restart the browser and see if that helps. Also, how is your PC connected to the monitor? I sometimes find HDMI can mess with the quality, switching to DVI/VGA helps.
All started when i installed a new font and it didn't render on-screen correctly, so was deleted...