Images in cam but not PC

I plugged my 4gb MD into my card reader and began to sort the files by type (within windows by right clicking on group and sort by type). Everything went blank and took time loading, so I pulled my card out. Now when I put it back in, there are no folders. Right clicking the drive says it has 0 bytes free space and 0 bytes used space. I plugged it into my camera and can see all the images.

How do I go about getting them on the pc?

Thanks

Restarting the computer fixed the problem. I know I should have restarted the computer before posting this question, but the images I took were of a football (soccer for u Americans:p) game that a nationwide paper asked me to shoot. Not getting paid or anything, you can say its a favor.