This may be a dumb question, but did Loop Cut and Slide get removed with Blender 2.74? I have 2.73 and 2.74 both on my computer, and it works fine on the old one, but when I go to User Preferences and try to change the key it's mapped to in the new one, it's just not listed at all. I tried resetting to factory defaults and uninstalling/reinstalling, but the option still isn't there.
Edit: I should mention my OS is Windows 7 64-bit with the installed version of Blender, not the portable exe. When I try to use Ctrl + R on a mesh, nothing happens. I've attached a screenshot of what happens when I go to Input prefs and search for actions using the shortcut "Ctrl R" in 2.74