Hello Kwok,

The factory reset will have greater impact than a removal of the power cord alone (as evidenced by the time it takes to reload your customized settings). However, the recommendation to first check that the "opr/srv" switch has not slipped into the "srv" mode is a good one. If this proves not to be the case, then perform the reset.

If neither of these suggestions restore your unit to normal operation, please contact us so that we may assist you further.

Best Regards,

Scott