Try to put a trimpot or potentiometer into LCD VEE power rail (like example).
Where the crystal osc??? EditIt should be as close to mcu)
Where the MCLR pull up???
Check all connections!!!
Edit: Put too a capacitor 100nF decouple (It should be as close to mcu VCC power rail)
I suggest you to place 33pF capacitors to both lead of crystal.if you don't get what am i telling then try to googling...let me expalinn you in steps
(1) Check power supply of LCd as well as also of uC. it shold be 5V
(2) Check clock circuits i dont know how to check crystal but mainly is is not damaged....you can check wiring of it and by physically damaged signs.
(3) Check connections of LCd and uC.
(4) Check reset circuit
(5) It is necessary to place some delay in programming while interfacing LCD so just check your software....
(5) If everything is a ok then replace LCD
Don't give more than 5V to the circuit. Don't charge the battery onboard. Charge it somewhere else and use it in your board. Try adjusting contrast of LCD.