My microSD is not working

Hello,
iam using microSD 1GB in my nokia7210 supernova. My memorycard is working my mobile and i able to format it. But it is not detecting when i connect it to computer through usb datacable. I think i had put password for my card. But i forgot the password. When i connect my mobile to computer my memorycard is detecting. Iam unable to use my card with other mobiles. Please tell me the solution for that and how to recover my old password to enter the new password