Broken Screen Help

[jordnbball08]

Today my phone fell out of my hoodie pocket at work without a case and when i went to use it the next time the back light came on but the screen was blank. i pulled the battery out but nothing changed. now the screen is half completely black and other half is back lit but blank. phone can still make calls and i am receiving texts and voice mails that unfortunately i cant retrieve. anyone have any ideas on whats wrong. do you think a sprint store will replace? Thanks in advance to anyone with advice. will it matter if i have a flashed rom when i take it in?