Memory card problem

Hello,

i m using 4gb memory card for noka x2..i have stored some photos yesterday(from pc) but i think these are viruses. my phone restarts when i insert but works fine without memory card...Now the problem is that i m unable to format the card. my pc detected the card but its not opening.. i have tried command prompt, disk management but nothing works...wheneve i tried to open it computer halts... i wud be thankful if you help me out