Hard reset is not working

Dear All,

I have a 750gl router. i upgraded the firmware to 6.27. for some reasons i want to hard reset the device. But unfortunately its not getting reset.

whn i press the reset button during the power up, the ACT light blinks for once after 40 seconds. after that nothing happen, i kept on pressing the button approx 3 minutes. nothing has happened.

Kindly help me on same. will be very great full.


Regards
Manjeet Singh

The most complete reset is NetInstall.
Video guide.