Greetings,
When did you notice this problem? Do you recall any changes you may have made in ArcGIS install, registry and/or user profiles folders? Could you please try to see if this is user profile specific issue? I.E. it happens only for one Windows user but not for other. To test this, you can create a new user and log in with that user and see if you still see the Envi. Settings window empty.
Thanks
Pavan