I powered down the router, rebooted the computer, and re-powered the router and same results. I reset the router (paperclip trick) and it ran fine for about 30 minutes, then the malfunction started up again. All these tests were done on an HP Media Center PC desktop, wired to the router. I also tried my Dell laptop with Windows Vista Business (wireless) which always ran fine before as well but it too gave the same result.
I connected my cable modem directly to the desktop and it runs fine.
I suspect that my router died. Can anyone confirm this, or is there an easy fix?