JJC1, you will need a router or something to assign the IP address to both machines. Most likely you have a firewall running, VPN, haven't enabled sharing of folders or your router is configured to DMZ mode your laptop or wireless setting.
With both your PC and BDP on, go to the front panel and find the IP address assigned to it. On your Windows 7 machine go to "start -> accessories -> command prompt" and type ipconfig. Both IP addresses should be similar something probably like 192.168.1.100 and 192.168.1.101 where the first three digit groups (octet) match, and the last digital group is different.
If only the last octet is different then go ahead and ping the BDP to see if they are on the same local network. i.e. ping 192.168.1.101 If you don't see a word like "failure" then the network is connected properly, you just need to review your security settings on both your laptop and maybe even your router.
Jim