We used Nikon D100 for work for a couple years---until they pretty much did what you're describing and ultimately kicked the bucket. Not sure if it has anything to do with us wearing them out (I work as a high school sports photographer), or poor design, but we went through several. They were sent off for repairs. Not sure what the cost was, I didn't have to pay it. Now most of us are using Nikon D70s---with occassional problems, too.