Gary, After owning my D300 for a few months, I had what I thought were hot pixels last summer. Turns out my sensor filter was dirty. I can second Dave's advice--Copper Hill has a great kit at a reasonable price, and if you follow their instructions, your problem will probably be resolved. I was nervous about cleaning the sensor the first time, and it took me five or six tries to get it right, but after that, it seemed to be much easier. I am finding I need to wet clean about every 6 mos. now.