I have a DELL XPS M140 using Win XP OS, using a RCA Thomson DHG535-2 Digital Broadband modem through Comcast; and it has NEVER had a problem making an Ethernet connection. I recently purchased a DELL XPS M1530 using Win 7 OS, same modem, etc. It will NOT connect via Ethernet. I get a screen with the message: This Page Could Not Be Displayed. When I attempt to Fix Connection Problems, I get the message: "Local Area Connection" doesn't have a valid IP configuration; or Connection failed with error 651. I have disconnected the modem and computer, waited a few minutes, then reconnected everything again, but I am still NOT able to connect to the Internet. I have checked, and the DHCP configuration is as it should be. I have tried releasing then renewing the IP address. No change; no Internet. HELP??!!

Find some ultimate steps to fix the issue of the Connection Failed With Error 651 in the blog. A windows user may have encountered the error 651 when they try to connect your PC (Windows 7/8/8.1 or 10) to the internet using the broadband connection. Other reasons are sys file is misplaced, your registry is corrupted, IP address conflict, etc. In this case, a specialist is recommended to solve these problems.

I had faced this kind of error on my device also. To resolve these issues I read many blogs and articles on this topic. Now I can fix this kind of issue but can't post the full solution of Connection Failed With Error 651. If you are undergoing this kind of problems then you can communicate Windows support freely to get cooperation. A certified craftsman will help you out. I am sharing a link of one of those blogs, just read the blog and learn the procedure to determine this issue.

View the blog for Full solution:-
Connection Failed With Error 651

Hi there,
I have been facing the issues of Connection Failed With Error 651 on my Hp Printer. Which was very irritating sometimes. Then I searched for the solution of this issue, which lead me to some websites, blogs and articles. Where I found a few steps to resolve these kinds of issues.
I can't post the whole solution here, If you are facing the same issue, then I am sharing a link of one of the blog here. Just go through the blog and follow the procedure.
View the Original Blog:- https://www.hptechnicalsupportphonenumber.com/blog/how-to-fix-hp-recovery-manager-error-code-ffffff15/

Mine Was Doing The Same Thing I Had To Ring Up My Internet Supplier And They Guided Me Through Over The Phone

Ok, well it could be the following
First off you should, Turn off your antivirus (just for testing) disable or uninstall Microsoft Virtual PC, it causes issues, and lastly disconnect IPV6.
90% of places and routers, and device cant support it yet. To see if its on, in windows,
click start, in the text box type CMD and hit enter
A black command prompt will show up
type
ipconfig /all
Scroll back up and if you see numbers other than Os in IpV6 its connected, you need to disconnect that.
TO do it that
click on your wifi signal in the bottom right of windows, go to open network and sharing access.
On the left, choose change adapter settings.
Per your connection type (wired or wireless) right click on it on it and go to properties.
under the setting Internet Protocol Version 6 (TCP/IPv6) uncheck the box if its checked.
hit OK.
Do this for all listed.
Restart windows.
Still a no go try the following
1. Check to see if the router needs a firmware update? When was the last time you did that?
2. What are your security features on the router. Your not MAC filtering or anything like that are you.
3. The card for the new Dell, what type is it. NIC is what I am talking about, is it B/G/N type. Or G/N. Does your router support 802.11 G/N or just A/B
4. Are you doing this WiFi or hardwired, I assumed hardwired cause you call it Ethernet.
5. Reset the router with no settings or security at all. Save you current router configurations first (if any) and there should be a button somewhere that you use a Pen to push and reset. Hold for 10 to 20 secs or longer. Now its a empty box until Comcast updates it to a new modem. (must do this to power cycle the RCA modems)
6. What is your NIC card? With a new system its a Gigabit, does the Modem support it. It shouldn't matter but check the cable too. Gigabit cards have bit parity meaning the can switch the bit. If you are using a cable that is wired different on each end, and your modem needs it to be wired the same on both ends it will never work.
7. Are you using a router also.
So here is what you should do.
1. Update all Win7 OS divers and software.
2. Update your Router Firmware if you have one.
3. If possible update your modem (usually you cant).
4. Unplug the modem and router (if you have it)
5. Plug in the modem, then press the reset button in the back until it reboots again (it could have old settings stored in it from where it came from.)
6. Plug your router into the modem(if you have it)
7. What on you Dell is managing your NIC. Is it windows, or Intel or what. Turn off all management software that is managing your NIC. Use windows if you are not using already.
8. Plug in the cable, and do the following
Open your browser hit stop and type the following
192.168.0.1 does it get to a admin window
then use
192.168.1.1 doe it connect to a admin window
192.168.100.1 or 0
this should get you into your admin screen in the router.
use the user name admin and password admin
or leave the user name black and type admin,
if that does not work look to your documentation.
if you can get in reset the thing and clear all settings within reason, if you are not OK with this, don't do it
NEXT
Run Ping and Tracert
How to use the ping command
Windows 7, Vista or XP:
Click Start->Run and type cmd and press Enter. This will open a black DOS window. When open, type ping -t www.comcast.net and then press enter.
The output will look like this:
Pinging www.comcast.net with 32 bytes of data:
Reply from 204.127.195.15: bytes=32 time=75ms TTL=46
Reply from 204.127.195.15: bytes=32 time=75ms TTL=46
Let this run for about a minute or so and press Ctrl and C to stop it. In the output, look for how often a Request timed out message appears and also look to see that the time=XXms part of each reply is as low as possible - below 100ms under ideal circumstances.
Are you loosing packets is so then nothing is getting out.
Tracert
Run a traceroute
Sometimes it is helpful to run a trace if you are having difficulty with a specific destination or service.
Windows 7 & 8, Vista or XP:
Click Start->Run and type cmd and press Enter. This will open a black DOS window. When open, type tracert www.comcast.net and hit enter. When it is finished, you will see a "Trace complete" message.
Are you going to them, or not?
If not then the internal firewall in the router is stopping you and you need the ip Addy to the router to change this. Here is the guide to your router, read up
http://www.simplehelp.net/2006/07/15/cable-modem-troubleshooting-rca-dcm425/
Finally you will need drivers if the rest is not working for Windows 7 and your modem/gateway this is a driver for windows 7 and that router http://www.driverssoftwareupdates.com/d/dhg_535_2.html
other than that you have to contact Comcast, or get the info for the admin settings in the router.
Finally, are you using the USB type connection or RJ45 Cat 5 cable. If your using a USB then disregard the Patch cable thing.
Also if you have one connect with the USB (its a fire wire cable and being that you have a gigabit NIC in your computer it should connect with no issues.)