One of the clients is using TORRENT software or the security is WEP or less.
Hope this helps you sort it out.
I am on At&t and I have the White 2wire Modem. I have been having this modem constantly cut the internet (red light blinking) and then reconnect. At times (Usually Night is when it happens most). I have contacted At&t about this and they done some changes on the line..it did not fix it so I called back. They sent a tech out and he said that he done some more changes to my line and since we are on an internet only plan he turned off on phone lines except the one going to the modem.