Samsung star memory card troubleshooting

Hello,
I tried to connect my Samsung Star with PC via Mass storage.. Then I copied some files to the memory card and Safetly removed hardware.. When I disconnected the device, it starts to turning off and on again without asking PIN.. I tried to turned it off and on again but it didnt help.. So I had to put the card out.. Can u please help me with solving this problem ?.. I dont know if the card is wrong or the downloaded files.. Thanks..