Screen wont come on phone still on iPhone 3G

My iPhone 3G is on (it vibrates and makes basic sounds) but the screen is black (even on bootup, shutdown, and any other time) I got a white screen when my friend called me, so I know the screen is still working. I have tried all kinds of things. I have restored it 4 times with no result. Held the home and power buttons down in all kinds of combinations for all kinds of time periods. I just got my iPhone back from being refurbished two days ago. Im assuming Ill have to do that again. I am extremely annoyed at this however since I am now at my college with no store anywhere near me and absolutely no phone until i go home next week.
If anyone has something I can try, Im open to new ideas, but please dont tell me to just hold down the power and home buttons. Ive done that thousands of times by now. Anyone who is NOT an idiot and knows what theyre talking about, please help and thank you.
iPhone 3G iPhone OS 3.1.2