Cannot download files off of internet

2 out of 3 computers in my home, using the same Qwest DSL, cannot download files from the internet bigger than 5MB. These 2 computers, Dell Dimension8200 XP, and Compaq Presario C700 Laptop Vista Home Premium, we both rebooted with reinstallation CD's back to factory settings. I was able to download Windows updates (after numerous attempts). But when I try to download freeware off of the internet using IE7 on both, it freezes within the first couple of minutes, then about 10 minutes later a window pops up informing me that either the connection was lost or could not be found, or that the it timed out. I have gone into internet settings, deleted the history, reset the settings to default, and even went into the registry and expanded the time out, and still nothing works. I am worried that my son had been downloading things off of the internet through torrents. That is why I rebooted both systems. The other computer, which is my personal home computer (never allowed the kids on it), didn't reboot this one, downloads things fine, so I don't believe it's my internet. PLEASE HELP!!!