Thanks for the replies. My phone has this problem.
HTC diamond screen problem solved!(Microp error) [ Assistance Cont. by Request ] - xda-developers
The screen goes black. If I remove the battery and put it back, the screen starts working again and the phone powers on with the message "microp version mismatch" - which supposedly indicates a hardware problem.
Not sure what I'm gonna do now as I've heard that cellphoneforever are hard to get refunds from.