Is this the demo that isn't displaying the EFIS? Or is it the 757-200 Base Pack?
If it is the demo, then as far as I know, not all the instruments are included in it. My guess is that the EFIS isn't included.

Please note, the following features are not included in the Free Demo:
• Extensive Systems Programming (ADI, HSI, EICAS displays inop)
• Flight Management System (CDU inop)
• Realistic Flight Model (flight controls locked in the Demo)
• Custom system sounds and crew voice messages
• Authentic Sound Set - PW and RR engines (alias to default 737 sounds in the Demo)
• Collins WXR-2100 Weather Radar
• Aeronautical Data including Terminal Procedures
• Repaint Kit

If it is the Base Pack that is having the problem, then the Demo version must be uninstalled before installing the Base Pack. It can't be installed over the top of the demo version.

When you done using the Free Demo just click:
Start > Programs > Captain Sim > 757 Captain DEMO > Uninstall
The Free Demo must be uninstalled prior to any 757 Captain product installation!

Mark