enable interuupt change state tu use keypad with pic16f876 and lcd

hello every one,
my objectif is to write a program with mikroC pro for un pic16F876,LCD and keypad...i tried to use the library keypad earldy existed in mikroC pro when i simultated in ISIS is working perefectly but when i put my program in hardware is not work i don't know why so i tried to look for an other solution by using interrupt PortB change state (RB4, RB5,RB6,RB7) but when i similated the program in ISIS i don't see any change of state at this four Ports.
to be more clear i enable bit INTCON.RBIE, INTCON.GIE at function main
i tried to test INTCON.RBIF in onother function called void interrupt() if is true that mean i recieve an interrupt
but nothing work so can i any one give my any advice or show me where i made mistake ????

ligo.george said:

Did you use pull down resistors in hardware??
MikroC Pro keypad libraries are 100% working.. I tried it in proteus and real hardware..

Click to expand...

thank you for your answer...but what do you mean by using pull down resistors and where should i put it ?!!!

thank you soo much for your answer is herpfull and my keypad is working...

but i would like to see a series of number in my lcd so i noticed that when i pressed in first time the number appears but when i pressed for second time my last number removed and replaced by new one and when i pressed for third time nothing change i can see my series of number i pressed...

so do you have any idea , how can i hold the number of my first press !!!!!