Make sure to copy the stsadm to under the c:
C:>stsadm -o getproperty -pn developer-dashboard
C:>Stsadm –o setproperty –pn developer-dashboard –pv ondemand
The you will find a new icon beside the logon name in central admin
To disable the option or enable it
Stsadm –o setproperty –pn developer-dashboard –pv Off
To display the additional diagnostic information all the time, you use the same commands, but instead of specifying ondemand as the developer dashboard type, you provide a command to create an on/off icon that enables and disables the dashboard as needed.
You use the icon to toggle between displaying and hiding additional detailed diagnostics.