LAN gaming between 7 and xp

I've searched and searched the internet and can't find a solution to my problem.

My brothers and I enjoy playing LAN games together on our local network. We've got a 'Netgear Super Wireless ADSL Router DG834GT' (includes modem) two desktops running XP and my laptop which I just installed 7 on. The two desktops play multiplayer together fine, either one hosting or joining, but my laptop is the problem. The results depend on the game, though I've only tried three so far.

BG2: Throne of Bhaal - Either desktop hosting I can get to the password page, but can't connect after that. With me hosting, the desktops can't get anywhere.

SW: Galactic Battlegrounds - Desktop hosting I can see the game but can't connect. When I'm hosting neither desktop can see.

SW Battlefront 2 - Desktop's hosting, I can connect and play fine. When I'm hosting the desktops can't see again.

I've tried disabling all firewalls, followed the instructions here and am able to share files any which way I want, but just can't seem to play games. It's like my laptop's not sending the required information. We're all on the same workgroup, I've disabled UAC, I've checked the registry entries for restrictanonymous, disabled IPv6 on my laptop, but I can't work the problem out.

Btw, I previously had Vista and had similar problems but I could usually get it working by playing around with the settings mentioned above.

Any advice would be much appreciated. I've uploaded the saved info from running DxDiag if you need to refer to it.

Ok, so I don't like doing this, but I'm going to bump this topic, cause I can't be the only one experiencing this problem and I still need some help fixing it. Again, any suggestions would be greatly appreciated; I'll try just about anything at this point.

To me this sounds like the issue is on the XP machine with the firewall on the desktop.
I would make sure that the game you are hosting on the desktop is allowed to go threw the firewall. You can test by disabling the firewall on the desk top and host a game and see if the Win 7 connects.

When hosting anygame 70% of the problem is a software firewall.

Like I mentioned, I've already tried to host and connect to a game with the firewalls on both computers disabled so I'm fairly certain it's not a firewall problem. I know my router has an inbuilt firewall, but I'm pretty sure that only effects traffic entering or leaving the LAN, not within the LAN.