My screen went black and the phone wont turn on, but the battery is fully charged...

SOURCE: SGH G600

This happened to my old phone...try opening up the back and just move the sim card in/out/around (depending on phone)...then retry starting it up...it didnt fix the problem but every 5 times i had to do this....hopefully this will work...gd luck
lilolo

SOURCE: Sanyo 6600 fully charged battery but wont turn on

just simply take the battery out and the phone will shut off. You will not lose any contacts or other memory as long as the phone is on idle

SOURCE: Nokia 6500slide screen fades to black and white then offs

Its a Virus Problem CommWarrior.
Format Ur Mobile.

SOURCE: phone turns on and off but wont start

try using ur phone while plugged in charging. if it works thn ur battery defective

SOURCE: Sony Ericsson W910i wont charge or turn on?

i had the same problem, just recently discovered that if i plug the charger connector into the phone and bent it back at an angle towards the back of the phone(slightly, not much) that a red light would switch on on the buttons(strange). But anyways it would start working again then, dont shoot me tho if it doesnt work for you guys