Details
Ribbon has disappeared and cannot be displayed anymore
Solution
The Ribbon can be hidden/displayed by using CTRL+F1. If yours has disappeared, just use CTRL+F1 to have it be displayed again.
Hardware/Software Configuration
Platform: INTL64
OS: window
OS Version: 764SP1
Product: SOLID_EDGE
Application: APPLICATION
Function: UI
Ref: 002-8001582