Hi:
There are two ways to clear system board NVRAW.
One is to use of a maintenance swtich as you mentioned above,and the switch is located on the "2" position in the picture below.
And the other way to clear NVRAM is to use of a SmartStart CD,you can set the systemboard to factory defaults with "System Erase" tool in smartstart CD,but be sure you only select the option clear NVRAM.
Good luck,man！
