Ok, lets see what we can do. I have a similiar router so I can actually provide you with hands on advice (kinda).
1) Unfortunately I am not that familiar with McAffee products since I swore them off after a bad experience with them a few years ago. That said, it should be sufficient to disable the firewall when you want to play LAN games.
2) What Static IP addresses have you assigned to each computer? They should be in the same subnet. ie... I think the router uses 192.168.0.1 as its IP address. The PCs should be something like 192.168.0.10 and 192.168.0.11 if you are using static IP addresses. The reason they should be around there is that the DCHP server on the router will hand out at 192.168.0.50 to start and you don't want to interfere with it. You can have the router assign those static IP addresses to the computer (this is the best way to do it). To do this though you will need to find the MAC address of your network cards. Go to this site to figure out how.
http://www.artsci.wustl.edu/ASCC/documentation/macaddrss.html
When you have your MAC addresses for both cards, log onto your router. The IP address of the router will be 192.168.0.1. If you don't know how to do this then read the instruction manual that came with your router.... or go to here and get the manual.
http://www.dlink.com/products/support.asp?pid=6&sec=0#manual
After you have logged on, click on the DHCP button on the bottom left of the screen. At the bottom is a place where it says Static DCHP. Read in the manual about how to set this up.
This is the best way to set up static IP addresses as it will give each PC the same address each time and you will still be able to get your DNS servers without having to hardcode them.
If you are gaming or use some filesharing programs it is a good idea to use static IP addresses as you may have to set up port forwarding.
After you are done this part the computers should be able to ping each other. (part 5).
3) For Farcry it looks like there was some LAN play issues that were resolved with the latest patch. I haven't played the game yet (though I wish I had it).
http://www.ubi.com/US/Downloads/Info.aspx?dlId=691
I can't find anything for Battlefield 2 lan play, I'd say make sure you have it updated and maybe someone else who has it can help you out a bit.