Playing around with a computer directly connected to the modem vs. a router inbetween, I'm thinking there is something to it. Since I've got like 12 computers wirelessly connecting to the router, I'm beginning to think that there might be something where the router isn't hiding all the different IPs accessing it, and that info is getting through to the ISP. It's not a manual block, but possibly an automatic scripting thing on their end. As when I disable everyone except one or two computers, the signal stays up. Then if I've got everyone on it, and there's no more internet, I unplug the modem, wait a few second and then plug it back in. After it does its handshaking bit, it assigns itself the same IP as previous, but the internet is working again. (even when the actual internet access stops, the modem configuration pages still say the connection is active. So all this leads me to think that the ISP has set their servers to kill a connection that shows multiple users. Running this internet through a PC and using the XP ICS, I've had much less downtime.

Grafitti, that seems unlikely that they can detect the number of users shared through the same internet connection. You're not using any software or window's connection to connect to the internet, right? The Router will connect by itself. A router itself is just another PC. Sharing though a PC will be the same. And there's no way for anyone connected external to the router (including your ISP) to get anything connected inside the router internal LAN, except for what's on the router itself. Sharing multiple PC though a single router, is just as if 1 PC is browsing multiple webpage at the same time, from the point of view of the ISP. Maybe there's a limit to the number of connection you can make. You can try load more than 10 web pages at the same time on the same PC. If it stop working, then maybe your router or your ISP is limiting it. Sharing though a PC will not solve your problem.