Thanks for the advice.
Just got the D90 back last week, sent it to Nikon over a period of 2months, for at least 3 times. The first 2 times got the Nikon back the cleaned camera, focus ring, formated camera and ran some tests. I got it back each time as soon as put a lens on, and tryed a sd card or battery it would lock up again.
Finally told them to hold on to it and do further testing, explained that I could get it to work again by slightly moving the lens or camera, thought it might be lose ccd or computer part inside camera.
It has seemed to work for the last few weeks without a problem.
Nikon service has been great taking it back each time and working with the camera, the only thing lacking on there end has been followup email or notes from there site, but I could get further info by calling them up.
Got to run.