The manual or internet should tell you what IP address it defaults to (warning, my experience is a numbingly stupid one) so you can just use the crossover cable and set the PC interface accordingly. Since you have a Gb port in the PC so it's quite recent, you may not even have to use a crossover cable since the port may be clever enough to work things out (mine is).
Udderwise, you can just put the unit on the LAN temporarily while you set the IP address to something reasonable, then connect it to the PC.
Udderwise2, you could run DHCP on the second port via one of the many free DHCP servers for Windows (assuming that's what you have) and not worry about either of the above. I used one by a German guy called Ruttge, Ruddge or something similar; it performed well.