Samsung Slyde White screen help?

i have the samsung slyde sph-m540 and i havent dropped it today, the batterys fine, and i didnt drop it in water or anything and when i go to turn it on i can hear the samsung power up song thing but i cant see anything no "samsung" logo and not my phone screen, how do i fix this? is there like certian buttons i press or what? PLEASE HELP!