arduino +lcd +gps

I am trying to connect a GPS module with an arduino duelminueve and also working to connect an LCD interface to it.
Have done everything possible.
When the GPS functions the LCD gives a blank screen
whereas the LCD functions well on its own for hello world or blink designs
plz suggest

I'd love to help. I've got my GPS displaying info on an LCD just fine. Perhaps if you gave us your code? You just didn't give us any details to help diagnose the issue.