Why I can not open the GPRS access it?

My phone card has been launched GPRS.
Phone settings are all correct.
Friends I play cards on mobile phones can access the Internet, why would I not do?

What is your card? many parts of the card is automatically launched GPRS to the Gprs just opened almost two hours before use.Unicom and other mobile Internet settings are not the same GPRS can not open Internet
However, it is estimated that the cost of your
your card problems
your card does not support this business is that you issue a card, call to fight to do to update your location.