USB that is burning me

[sheikhsa]

I was working fine and fixing THE USB problem that another problems comes in,
it become
Write Protect is on

there is no sign outside to lock the usb.
I tried
hdparm -r 0 /dev/sdb
it shows that it is now read write, but fdisk can't write in it.

I cannot write on the USB ..


Regards,
Adam

[falko]

How do you mount your USB stick? What are the outputs of mount and fdisk -l when it is mounted?