Cricket and tmobile use different network signals. Tmobile use gsm and cricket use cdma.

Firstly, open the back cover, take the sim out, remove the battery, now, carefully take a five pound hammer, rinse gently under warm water, sprinkle with sugar, and then crack the phone until it shouts "Cricket Cricket" if that dont work, I am stumped, hang on, Cricket! Stumped! Any ways, five pound hammer is the answer

put a trench coat on with nothing else and then flash it!!!