[aiiee]

This defect has been well documented here and elsewhere as a mfg defect. I had it myself. First the rainbow, then the small dark spot at which point the screen becomes non-responsive. Most people contact the carrier and get the phone immediately replaced. That's what I did. If it's under warranty you won't have to pay. Go thru the carrier. I'm amazed HTC tried to pimp you on that. They are rapidly losing any goodwill they ever had with me when I hear about stuff like this.