losing internet connection

For some reason I don't have a steady internet connection. I have cable but I also have wireless. However the problem isn't strictly the wireless. When I plug my computer into the wireless router, it keeps going out once in a while.

The reason why I know its happening is because my messenger signs out. This happens with both msn and yahoo. I know its not my computers fault either as it happens to my roommates laptop too.

Suggestions on where to follow up next?

 

DSL or cable ?
There is a switch in the router for dsl for connect on demand or always reman on.
If so try changing the setting.

 

Cable

also I don't see a switch on the router or my modem for that matter about DSL/cable.

any other ideas, its starting to get annoying.