Plug in NICs which have WOL have a little socket which you're supposed to put in a lead which goes to the corresponding socket on a compatible motherboard. It's highly unlikely that you've got the lead though as it usually doesn't come with the NIC.

That said, yeah, it's unreliable and even if it did power up your PC, how long are you willing to wait whilst your PC loads it's OS and finally the Receiver server software? Leave the PC on