You woz ROBBED!
http://www.badflash.com/removbio.htm - these guys charge less to supply AND pre-flash a chip.
Seriously, write protect can be applied at two levels, a jumper on the motherboard (get the motherboard manual), and a write protect option in the BIOS menu (the motherboard manual probably describes that as well)
If the motherboard is a Medion special (doesn't seem to be, as they tend not to have a standard MSI number), then some options may have been hidden in BIOS