Constant reconnecting needed

Hi all. I have recently set up a new internet connection. It is comcast cable, through a motorola SB5120, into a Dlink 524 router. It is WPA encrypted. My roommates and I have problems with losing the internet. We can't connect to webpages, and aim signs off. All we have to do is disconnect from the network, then reconnect, and everything is fine again, however that is really annoying. I am currently running windows XP, but it is effecting macs as well, so thats not part of it. Any ideas what might be causing it?

 

Well, since it's a common component, try this:

Connect one or more of the computers using an Ethernet cable and see if you still have the disconnect issue. If so...

Connect a computer directly to the modem and see if you have a disconnect issue. If so...

Register at DSLReports and run their line quality tests. Post a link to the results here.