Router kicking modem offline?

The problem I am experiencing is that my internet randomly goes out. I've contacted my isp and they say that the problem is likely due to my router kicking the modem offline. If i unplug everything, leave it for a minute, then plug it all back in, my internet is back online. If I plug a computer directly into my modem, the connection stays solid.

The router I'm using is a belkin wireless g router. My OS is windows xp. i have updated the firmware on the router.

Any solutions?

I'm no wiz at computers & routers and such, so i am sorry if the solution to this is obvious or anything.