Hi I bought Samsung Galaxy i5801 last week. But for the past 2 days, I see a strange problem. Sometimes, the screen goes blank. The keys are on and I could also receive incoming calls. The touch also works. I was able to blindly swipe the screen to receive call. The screen is off. I tried restarting and even then there is no display - no logo, but it boots. After 1 or 2 hr, the screen comes back again without me doing anything. I have given it to the service center. Do you guys know what could be the problem? manufacturing defect or software corruption? Any response would be appreciated. Thanks!