Thank you very much for your answers! finally i bought 2 new nRF24L01 chips and now with the same code it is working normally! the code that i used and i use is from the Mirf ping example. The version of Mirf is the latest that i download it here: Arduino Playground - Nrf24L01.
I discovered that the old nRF24L01 chip is burned and i have no idea how this happened because it is connected to 3.3V as it should be! i red somewhere that we need to add some resister to protect the module by using the 10K and the 15K resister to reduce the voltage. So my question now is do i need to use resister to all the pins? And my second question is why this chip has 2 Vcc and 2 GND pins?Do i need to connect 2 Vcc and 2 GND or not? right now it works only with 1 Vcc and 1 GND.
I am waiting for your help please!