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Question: i can't charge and use my C901

i turned off my C901 after i deleted some photos and updated my media..when i turned it on again..it says "use a correct sim card"..so i turned it off again..i removed the battery and the sim card..after a while..i reinserted it..now it says "you cannot charge the battery. use a sony ericsson battery"..but it's a sony ericsson battery that i used..and there's no defect with the charger..i don't know what's wrong with my phone..what shall i do?