Please help using remote assistance

[Sully]

I have been trying to get into a freinds computer using remote assistance.
We both have XP. He has a linksys router and has two computers sharing his cable connection.
How can I disable his firewall so I can get in and help him with a program.
I use it with other people without a problem. I just can"t get through his router.
I need a step by step example on how to open his network using the linksys software.
please explain as you would talk to a 10 year old.

Please help

 

[rebuilder]

Is this any help?
From Windows Update:

Remote Assistance Used with Network Cards and Firewalls
Download size: 350 KB, < 1 minute
This update resolves the "Remote Assistance May Not Connect to a Multiple-Homed Windows XP Computer with the Personal Firewall Feature Enabled" issue in Remote Assistance, and is discussed in Microsoft Knowledge Base (KB) Article Q308210. Remote Assistance can fail when the user is behind a firewall and has multiple network cards. Download now to use Remote Assistance from behind a firewall with multiple network cards. Read more...

 

[Sully]

I downloaded the file but how do I configure the router to except a connection?