Can someone explain to me how my storm2 worked with an ATT sim card and for some reason now when the ATT sim card is installed it is not recognized.

What do you mean by "worked"?

Is it a 9530 as per your profile or a 9550? If the latter, please update your profile with the correct model number, not the name.

Is your SIM inserted in the right slot and in the correct orientation?

Have you activated the device? Do you have a BB data plan?

See the yellow sticky at the top of the 9500 section for instructions on how to make it work.