Application Display Alert

Hi,

i have saved one workbook with password protection.
Whenever I open the workbook
and uses Save or Save as it displays the message.

"This Document is both encrypted and password protected..............
.......Do you want to increase the security by converting
to an open office XML format? Yes No "
I always press no and saves. how to disable this message.

I have tried using Application.DisplayAlerts=False.
oops but no use.

Thanks

rjayaram.rj