My N900 developed a screen problem after a couple of months. The touchscreen became unresponsive especially in the top left hand corner. I sent the handset back, they said they had fixed it, but i think all they did was reflash the whole device. so i left the device empty ( with no apps on) for a while, and the problem came back. In the end, they replaced the handset with a new one, and this one has been fine ever since. Mine must have had a dodgy screen. Thought I would let you know what happened to me.