Yes, Web client and WebServer sketch work correctly, my SD card doesn't work with SdFat library neither Arduino SD library.
In that case I don't know what might be going wrong, except perhaps power problems:
Are you using the USB of a desktop PC to power the Arduino board? A notebook PC? A tablet? A passive USB hub where other devices are connected?
SD cards require relatively high currents, up to 300 mA, and desktop PCs can easily deliver up to 500 mA at least at their USB jacks. But notebook PCs or tablets sometimes only can provide 100 mA with their USB adapter.
Also passive USB hubs may create problems if other devices are already connected to the USB hub.
In that case try an "active USB hub" that provides USB power from its own power adapter! So that you can be sure, that the SD card (and Arduino/Ethernet shield) may draw at least 300mA from the USB port without voltage dropping down.
People have told me that can be a the ethernet shield becuase it is a clon, i bought it in amazon
Yes, it is true: Building quality of China made clone boards and shields is poor, and in rare cases it is possible that defective boards/shields are shipped. It may happen, but not very often (I think).