To change the signature of a disk under Windows 7, follow these steps are:

  1. Run the command line utility diskpart as the administrator user
  2. Execute the command “list disk” to locate the disk you want to change the signature
  3. Execute “select disk n” to select the disk where n is the numeric id of the disk (0, 1, 2, …)
  4. Execute “unique id” to display the selected disk signature
  5. Execute “unique id signature=hhhhhhhh” to change the selected disk signature. hhhhhhhh in a hexadecimal dword
  6. Execute “exit” to quit diskpart
  7. It is recommended that you reboot your system

DISCLAIMER: YOU DO IT AT YOUR OWN RISK.