both the computer and projector are running the same resolution
If not, identify the native resolution of the projector (i.e. 800x600, 1024x768, 1280x124 window within your operating system and select (click) "Advanced Properties". Locate "Refresh Rate" click and select "60 hz" as this is a known more...
NEC MultiSync LT84 Multimedia Projector - Troubleshooting
1280 2 1024 85.02 91.146 157.5 Y / N Signal Resolution Refresh Rate Frequency H. Dot Clock ( Dots ) ( Hz ) Signals in above list flagged with an N and shaded are not supported. #Y: Images in above flagged with # and Y are more...
NEC MultiSync LT84 Multimedia Projector - User Guide (page #41)