Currently Being ModeratedNov 21, 2013 11:56 AM (in response to rania1911)
By "reset" do you mean reset it to factory setting to prepare it for a sale (erasing everthing) or are you trying to reset the hardware becasue of boot or other issues?
If the former:
See > Apple What to do before selling or giving away your Mac
Also See Thomas Reed's How to Prepare your Mac for sale
and this thread