My 5150 says that the port is inaccessible for the modem to turn on, but running all the diagnostics and they say everything is ok. Now what?

Try to upgrade the routers firmware.
http://www.dlink.com/us/en/support/product/dir-615-wireless-n-300-router

Some ISPs (Internet Service Providers) limit you to *ONE* unique computer connected through the cable-modem (or DSL-modem).
Turn the cable-modem off.
Turn the router off.
Connect the cable-modem to the router, via an Ethernet cable to the 'WAN' port on the router.
Turn the cable-modem on.
Turn the router on.
Connect, via an Ethernet cable, from one of the 'LAN' ports on the router to your computer.
Restart your computer.
You should be OK.
If not, telephone your ISP, and get them to trouble-shoot from "their" end towards your end.

Phone line cable ok?
W7 uses dynamic addressing so should set port automatically.
(assuming you mean Windows 7)

hello,

Connect your modem to the phone line and test the modem.

Control Panel-->>Phones and Modems. Click icon. Tab Modem. Highlight your modem, and Click Properties--->>Diagnostics. Verify that everything is OK.

Then Start --->>All Programs -->>Accessories-->> Comunications ---Hyperterminal.

Enter a name for a bogus connection, Click OK
Enter your phone number and dial it. If Phone/Modem connection is OK, you shoul hear the busy signal.
Alternative:Run the Dell diagnostics.

If Modem connection is correct you must then create a dialup connection.
Hope it helps.

Hi,
Thanks.
If you buy the new modem, make sure that you can return it if that's not the problem. Also, explain to Comcast what the problem is and that it happens on both computers. It could be a poor connection on the cable wire that goes into your home.

I had a similar problem and my DSL and Verizon found that the squirrels found my telephone wire rather tasty and ate through most of it..thus causing the bad connection.

Good Luck,
Hank

Well the modem should be connected to the UPLINK port on the router(the port without a number) both computers should be connected to the numbered port. Ensure you do NOT have a problem with one of your cables.

Check if your system is able to get an IP address.

Bypass your router to check if its a router connection problem. Connect your computer directly to your modem.

Click on Start>RUN>Type cmd then press enter. On the black box, type ipconfig /all. Check if your system has an IP address. If it says 169.254.x.x or no IP address then there's a oroblem with your connection. Power cycle your modem, router and computer then check your IP address again.

Power cycle your devices: modem - router then computer.

why fight it , let it be on com 1 then,
go into the bios and disable the serial ports .
that may be the easiest fix as long as you don't need the serial port for anything.
but if you have a serial mouse oh boy.

Do you have access to another laptop that you could test the new modem in? Sounds to me like the new one maybe faulty :(

Try uninstalling the old one whilst its in via device manager then shut down and put new one in. If it doesnt detect it then its faulty.