Such P2P programs can cause internet issues because of their file sharing with the entire world.. It's also a reason why some types of universities and ISP's tend to block IPs that are using such.. Easiest solution, have the roommate get their own service..
Another option is the router/modem doesn't fully support Vista.. We've found a few such issues which were solved by updating the firmware on the router/modem. Visit the manufacturer's website and see if newer firmware is available..
Hope this helps.
I've got an issue where my internet connection has been cutting out a lot lately ever since a new roommate moved into my apartment. Everything will be working fine, but then all of a sudden it will lose the connection. Firefox or WebKit won't be able to reach any web sites, Adium won't sign me off right away, but I can't send or receive any messages or check profiles. I thought at first it was my computer, but then my other roommates mentioned the same issues to me. I can't send a ping out. Even a reboot of my computer wouldn't help. The only thing that fixes it seems to be rebooting the modem. If the new roommates laptop isn't around, then things run just fine, but if she leaves it on and goes out for the day, the internet connections go down again.
I'm on a Macbook running 10.4, and have an iPhone 3G. One of my roommates is on an older MB Pro, and another an HP running XP. The new roommate has a Dell and is running Vista. We've got a Motorola SBG modem from Comcast that has wireless capability, but I attached an AirPort Express to it via network cable so I could use the Draft-N speeds.
Now, i don't know for sure if the cause for this is the new roommate's computer, but I can safely assume it is given that the issue started when she moved in last week, and doesn't seem to come up when the laptop isn't here. She has Vista, and I don't know a whole lot about it and what its capabilities are for FireWall or VPN. I had a similar issue before when connecting a VPN in XP to my work email, and it would lock out all other internet traffic until I rebooted the modem and router. Her OS FireWall is on, and it looks like she does have BitTorrent on there (and I know there is some port forwarding involved in torrenting, just don't know to what extent... but the modem doesn't appear to have any port forwarding on).
I'm at a complete loss for what might be causing this, and what we can do to fix it. Any help would be appreciated.