Well, E uses as a default font Verdana, so try to look into the Fonts folder and tell me if you can see it there. If you do see it there, one of them should be either regular or without any appendix (such as italic or bold). If you don't have one such, backup the fonts (just by copying it elsewhere) and try this: http://www.thewindowsclub.com/how-to-restore-default-fonts-in-windows-7
Reboot system (and browser). If that doesn't help, get out the hammer.
Edit: After you reboot, you'll re-install the fonts by selecting all of them (click on the first one, hold SHIFT and click on the last one), then right click, install fonts (click NO TO ALL when the computer asks whether to rewrite existing). When they're re-installed, you can delete the backup folder.