internet connection issue

can somebody please help. when i rj-45 directly from a spectrum supplied modem into a hp pavillion, boot the modem then power on the pc, the orange light on the back of the modem does not flash and i do not achieve an internet connection.

but, when i rj-45 from the modem into a linksys hardwired befsr41 router, then from the router into the pavillion, then boot the modem, power on the router, then power on the pc, the same problem does not occur. obviously from this description there is nothing wrong with the pavillion's rj-45 port. any ideas,,thanx