CC3000 Wifi Shield and Mega 2560 connection problem

Hi guys. I have a problem with CC3000 Wifi shield and Arduino Mega 2560 R3. I can't make connection. I want to see and control someting (digital and analog sensors, leds) via internet. I tried all Adafruit examples and all Arduino Wifi examples but it never run! Adafruit examples said some random characters, and Arduino's examples said that: "WiFi shield not present"... My wifi shield right attached to Mega 2560. Can you help me? What's wrong???

Quite a late response, but in the case of the Adafruit examples, the random characters might be an indication that you set the wrong baudrate. For the CC3000 shield, the correct baudrate for communication with the serial monitor is 115200.

and wifi shield Which is the problem ?

sounds like he didn't solder over the jumpers for the ISP/connect the ISP