Keep everything connected, its always good to be optimistic, go into the bios straight away, and check to see if the CPU is set at the right speed etc. and put the boot order in the right sequence.
Sata hdd don't have the pins, but for IDE does. it should have something like "M. S." and another one, I don't have a IDE hdd arond so I can't check. M. is master, and S. is slave, set it to the appropiate one, probally master.