problems with my linksys router

[dlandis72]

I have a comcast cable internet connection that is transferred to 3 computers through a Linksys wireless g router. For the past few weeks, my internet connection has been unreliable to say the least. Sometimes it stays connected for hours and sometimes it only stays connected for a few minutes, but it always disconnects and stays disconnected for a while. I call comcast and they said that according to their diagnostic test, my cable modem is fine, so the router must be the problem. I right click on the network connection and click "repair" but it never works because it can't "acquire an IP address." Does anybody have any suggestions for me? The router is only a few months old and I haven't really messed around with the settings much. I have never updated the firmware. Would that be a problem?