Arduino IDE menu doesn't display properly (missing letters)
I've never had this problem, but here are some things you might want to look at.


Did you install it from an administrator account and use "run as administrator"?  If not, uninstall and reinstall.
Its possible that you are missing a font, god knows which one.  Go and look at the Arduino source on GitHub(?) and find any TTF files and install them.
Does this version support Windows 7?
What version did you have previously? Did you uninstall it before installing this?
If you didn't have a version before this one, uninstall this version go and get 1.5 or 1.6 and install that, then install 1.7 over the top.


Good luck, and keep monitoring the Arduino.org forums because if it is a problem with the app then they will start screaming quite quickly.