My screen Has turned black with Blue lines blue lines running through it. How can I fix this?

Sounds like a hardware problem with the LCD or something else.

First you need to determine where the hardware failure lies. Make an appointment at an Apple store if there is one nearby where a hardware diagnostic can be run to determine the hardware component failure. If not, you need to visit an electronics repair shop that works on iPhones to determine which component has failed and needs to be repaired or replaced.

Currently, Apple has determined there is an issue with the AMD Radeon 6970M video card and will replace them free of charge for up to three years from the date of purchase. If you already replaced it call apple for a refund. Then sell the unit to another sucker and run like the wind.

Did you drop your phone? Sound like your glass is fine but your LCD is broke. Need to take it to an apple genius bar at your local apple store and let them look at it.