PIC 18f452 and PICKIT3 programmer

I was simply making a temperature senso using LM35 and PIC18f452 on my hardware kit.
and using PICKIT3 programmer to program the controller using ICSP when the controller is programmed it works fine and temp value is displayed on the LCD till that time the PICKIT3 pcb is connected when i remove PICKIT3 from that ckt LCD shows black boxes not issue related to power. then what could be the reason behind please help me out.

Can you give your lcd connection,pickit and your Code? more easy to help you