The Vista to XP Lan Games connection problems Solution!!
After trying to play several different lan games with my Vista equipped machine and not being able to join I finally found the way to make it work!! OH JOY! SO many forums browsed in vain. Finally I found it. For all of you, the problem was ipV6.
To fix that problem you need to disable ipv6:
1- Open the Network and Sharing Center in the Control Panel on the Vista equipped machine
2- Click on the little blue letters "View Status" next to your LAN connection (my wireless connection for me)
3- Then click on the Properties button (not wireless properties or anything else, just properties)
4- Click continue on the little annoying pop-up vista window if any
5- Now look for the field under "this connection uses the following items" there with Client for Microsoft Networks/QoS Packet Scheduler etc. You should find many of those with little checkboxes next to them.
6- Now i'm not very sure if it's only ipV6 that you need to disable, so to make sure, do steps 1-5 with you XP equipped machine to check what they have in that field, and keep the checkboxes checked for only those items. Uncheck everything else. I uncheked Internet Protocol Version 6 (TCP/IPv6) , and the two Link-Layer ones.
7- Try again to join your lan game it should work fine ( it did for me and our Dungeon Siege 2 Lan Party!)
Hail! to the Grand Superlapin that saves us all!!!!