I have a Seagate 500GB external hard drive that was formatted on my Macbook at FAT32. I was using it without problem both on my Macbook and my brother's Windows 98 desktop. I tried to use in with my new laptop, running Windows 7. I found out I had to assign a volume letter to it in order to see its contents. I did so, only to get a message asking me to format the drive! Moreover, now I cannot use it neither on my Macbook nor at my brother's desktop... I tried removing the letter but nothing changed; it is still unrecognizable, telling me that no known operating system is installed in it (or something like that)... I guess it's a disk header thing (after assigning a volume letter). Maybe I could fix this with some kind of software?
Any help would be greatly appreciated!