My issue is nokia n900 starts fine. After not using the screen/phone 5 minutes, I can't get the phone screen back. I tried touching the screen, screen is not coming back. All I get is the black screen. Phone is on. When some one calls screen comes back. I have downloaded some apps from nokia maemo dev and dev-extras repos. Culprit is one of these apps messed up my screen.

How can I get back. I don't mind clean install. Can someone guide me how I can do this.

Thanks.