Remove the battery cover and the stylus. Push the battery cover upwards, and then, remove it. Then you can find the reset button. Press it to reset your phone.
GigaByte gSmart S1205 WM6.5 hard reset (for Gigabyte gSmart S1205 hard reset with keys scroll down)
Restore to Default gSmart S1205 Cougar Dual SIM Clean Boot
Tap Start > Settings > System tab > Clean Boot. Input the 4-digit password in the blank, and then, tap "Restore" to restore to the default setting.
Gigabyte gSmart S1205 hard reset with keys/buttons
Press Camera + Power + Volume UP buttons
Press VOLUME DOWN to restore manufacturer default