Download Dccrap Modem Unlocker (google for it)
insert the modem into your pc
Select the make of your Modem from the Manufacturer's List and also Select the Correct Model of your Modem from the Drop-down (u can use auto select if u dont know)
Click on the Microscope Icon to Auto Search and Detect your Modem.
Tick on the Read Unlock Code & Auto enter to Modem
Click on the Do Job Button and your Modem will successfully Unlocked.