how to formate a write protected memorycard?

hey guys, anybody there? i have a problem. im using samsung galaxy ace GT-S830 with custom rom 4.2.2. i just partion my 8GB memorycard using minitool partion and woked fine for a while. but now i can"t install new apps into ext2(partioned sd card). also i cant copy or delete anything in memorycard. i used minitool partion, partion guru, easeUS partion master, but nothing works. i tried formating by windows diskmanager also, nothing works. still i can read files from my memory card... plz help me.:(

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