How can I unlock my memory Card?

hi there,
I'm using a Nokia 7210 Suppernova with a Kingston 2GB memory card. I don't remember giving the SD card a passward but if I did, then I forgot it. I was play music using the phone from the SD card and while it was playing, I tried to access another music folder just to change the geere that was playing at the time. But the folder took long than usual to open so I was forced to open the phone, remove the battery to short it down. When I powered on the phone and tried again to access th SD, it started complaining of formatting it. I did not but powered the phone on and off to refresh the SD but it later requested for password to unlock even when I try to format. Both phone and SD are less than 3 months old. It can be detected on Laptop SD, only on my phone
Somebody help.