cannot obtain valid IP address / cannot renew IP address

Have you tried shutting down the machine, unplug the power cord from the modem. Wait a minimum of 30 seconds then plug the power cord to the modem back in then power up the machine and see what happens. Sometimes the modem just needs a flushing of its own.

Another Expert shekerra found out what the WinSockXPFix does:

1- Netsh ip int reset resetlog.txt....2.)

2- replaces these Registry keys:
 HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Winsock..
 HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Winsock2

3- backup old host file and replaces host file

So in essence it detects the OS and releases the IP then resets TCP stack using Netsh. Next it deletes the two registry keys above and Imports the correct keys into the registry. Then it backs up your current hosts file and replaces it with a fresh one and then reboots.

Also

"The Page Cannot Be Displayed" Error Message When You Try to Start Internet Explorer
http://support.microsoft.com/default.aspx?scid=kb;en-us;326155

Error Message:"Page Cannot be Displayed" When You Browse the Internet
http://support.microsoft.com/default.aspx?scid=kb;en-us;812336

Blank Page or Page Cannot Be Displayed When You View SSL Sites Through ISA Server
http://support.microsoft.com/default.aspx?scid=kb;en-us;283284

Page Cannot be Displayed" or "Web Page Unavailable Offline" When You Browse to Http://Localhost
http://support.microsoft.com/default.aspx?scid=kb;en-us;290766
========================

When it comes to the NIC that the modem is connected to do not assign a static IP address. Comcast will assign one every time you either disconnect the modem or reboot the system.

I had the same problem when i had to reinstall my Windows XP. Its not the hard drives. You should have recieved a disk with the modem like a comcast install disk. With me I was connected from what they said also, the thing is even though its a cable modem it still runs off of password and username. If you switched out your hard drive then the computer no longer has that in memory to give to comcast. What I had to do and I suggest is to reinsert the Comcast Disk and Reinstall it. At some point it will ask you for your username and password this will be on your receipt from install or you can call comcast and they can tell you what it is. Once you reinput this information you should be able to connect to the internet no problem. So like i said if you have a disk just reinstall the stuff on the disk it will walk you through it all and ask for the info...Please get back to me and let me know if this helps you...im hoping that like me you will be back online in no time

Is the modem connected via USB or NIC. If USB and you have a network card (or onboard NIC) it may be trying to use the wrong connection. Disable the one you aren't using.

Chris B

I saw CrazyOne already mentioned abt WinsockFix.exe,,,,, but i think that the link is not included,,,,, here u can download it :)

Try running this Winsock Repair for XP:
http://www.spychecker.com/program/winsockxpfix.html

Umm SheharyaarSaahil that is because it appears that BobertBurke already has the exe but can't get it over to the troubled computer :)

hmmmmmmmm its always Better to first take a cup of coffee and then login on EE ..... =\
my bad ........ !!!!

CO feeeling better today, or ur wife must be outside ;-)

Well in about 1.5 hours I have a Doctors appointment and My Dad was admitted to the hospital this morning so I will be dropping by there to see how things are going

Hey guys thx for the help so far.  Heres some answers to your questions:

Comment from CrazyOne
"Have you tried shutting down the machine, unplug the power cord from the modem. Wait a minimum of 30 seconds then plug the power cord to the modem back in then power up the machine and see what happens."
-Yes, when I called Comcast each of the 3 times they made me do this, plus another few times I did it on my own - no help
"When it comes to the NIC that the modem is connected to do not assign a static IP address."
-I was trying anything

Comment from friendb4lovertn
"I had the same problem when i had to reinstall my Windows XP...."
-So I tried putting the disk in to reinstall the comcast stuff.  The first thing that happens when you put the cd in is it runs an account set up, and the first part of that is to check the service configuration.  This is a two part check: network adapter and a connectivity check.  It found my SiS 900-based PCI fast ethernet adapter with no problem, but the connectivity check failed.  The failure notice says "unable to establish a network connection.  This is probably because the modem is not connected properly.  Please check the connections."  I am unable to go any further in the setup so I never even make it to the username/password section.  Of course I have checked the connections many times, so I don't know what to do about this.

Comment from burrcm
"Is the modem connected via USB or NIC. If USB and you have a network card (or onboard NIC) it may be trying to use the wrong connection. Disable the one you aren't using."
-I am not using the USB connection.  I went to the device manager and disabled the USB adapter, leaving the ethernet adapter enabled.  Still experienced the same problems.  Do you think I should get a USB cable and see if the USB adapter will work and not use my ethernet adapter?

I am about to burn the winsock fixes to cd and transport them to the other computer.  If you guys have any other ideas, please feel free to let me know.  Thanks,

Your modem should have come with a USB adapter? but I doubt that is where the problem is. Does it still work in Win2000? And I know this is a wierd question but what happens when you do

Start > Run msinfo32.exe

if it errors out then the problem is probably a group policy problem. If not check to make sure you have the latest and greatest drivers for your NIC.

Here is a silly question.  Have you tried to run the create new network configuration?  And then set it to connect to the internet and follow the rest of the instructions?  Probably already have but just thought I'd ask.

Ok, so I finally got the winsock fixes onto my computer, and they did not help.  I was not sure how to use the LSP-Fix - It has .dll files that you can remove, but in order to do so you must click a box that says I know what I'm doing, but I don't, so I didn't.  Can you help me with what to do here?  The other winsock fixes, including the one for XP, did not fix the problem.  Some more responses....

Comment from CrazyOne
"Your modem should have come with a USB adapter? but I doubt that is where the problem is. Does it still work in Win2000? And I know this is a wierd question but what happens when you do
Start > Run msinfo32.exe
if it errors out then the problem is probably a group policy problem. If not check to make sure you have the latest and greatest drivers for your NIC."
-Yes I have a USB and an ethernet adapter.  I am using the ethernet but was asking if I should try the USB.  The device manager lists them separately so I did not know if one would work if the other was broken....  And yes, I just switched my hard drives back to the one that has win2000 on it and the internet was working....got all the same old popups, woot!  Anyway, I guess it has to be an incompatibility with winXP?  I tried the Run msinfo32.exe and it came up with no problem.  saw all my system info.  I will check for drivers - no any good place to download free drivers?

Comment from tmireles
"Here is a silly question.  Have you tried to run the create new network configuration?  And then set it to connect to the internet and follow the rest of the instructions?  Probably already have but just thought I'd ask."
-Do you mean the Network Setup Wizard?  I tried that once and it said that an error occured during configuration and recommended that I do it manually.  I have tried to create a network place as well, that did not work either.  If you did not mean either of these two things, please be more specific.

Thx for the help so far, but now that I know the winsock fixes dont work, I am really at a loss for something to try...Please help!

Drivers
http://www.network-drivers.com/companies/955.htm?acd=3&rvd=5&thx=9&bng=7&o=5

Thanks for the website CrazyOne.  I downloaded the newest SiS 900 driver and installed it.  After restarting my computer, I am still unable to access the internet.  At this point, do I just need to buy a new network card?  Or is there something else I can do?  Thanks for your help, unfortunately I will be going out of town tomorrow and will not return until sunday so I will be unable to reply to any postings for the next 3 days.  But if you have an idea please post it and I will try it out the second I get back.  Thx.

Have you tried to set the connection ip's manually. Make sure you set the modem's interior IP address as the default gateway. Also use that IP address as the preferred DNS server. Try simple first.    IP         192.168.1.1
                           Subnet 255.255.255.0

Sorry..... tab instead of space.

IP           192.168.1.1
Subnet    255.255.255.0
Gateway  use address of modem
DNS        use address of modem

The modem default address is probabgly 192.168.1.1

Get the address from comcast. If it is different make sure you use an appropriate address for you pc.

Hey guys, I have returned.  Thanks to GiffordNolan for the advice, I tried it but it did not work.  The network card was having a fit trying to work with my comcast modem and winXP.  So, as per CrazyOne's recommendation, I picked up a new network card and BOOM, the thing works like a charm.  You will be glad to know I am typing this while logged on to EE on my previously troubled and now fixed computer.  Thanks to all who tried to help, it is greatly appreciated.  

:)

Finally....the Winsock fix worked for me.  I have been batteling this problem for some time now and finally decided to come back to Experts Exchange. First page I ran across had my answer.  Great site and well worth the few bux to join!

Welcome chuck4 on EE..... and thanx for those kind words =)
Cheers to EE !!!!!  ^_^

I believe there is a much deeper issue at work here, something we have not yet discovered from the world of spyware/malware. I manage a major help desk for a large corporation and have seen this issue a handful of times. I have at my disposal all of the tools listed here and then some. In the every case, the same Brand and Model NIC did not solve the issue, but a different model NIC did???? More questions arose when the old NICs were tested and found to be in good working order. In one case 2 weeks after the new NIC was installed the problem reoccurred after running the usual Spyware removal tools. The PC was then reimaged and now works fine. (For the moment) Some piece of spyware has to be hooking into the XP OS in a place we have not yet looked.

My question: Can the MAC Address be compromised in anyway that would cause a PC to lose its LAN connectivity?

Theory: Spyware is hooking into the MAC settings somewhere in the Registry and causing XP to ignore the NIC that is installed. (Thus the inability to change the firewall setting) This also explains why a new NIC of a different brand with a different MAC solves the problem.

Any ideas?

Help??  I am have the same problem with the IP address on Win XP Home edition.  I have a comcast cable modem and it seems the PC IP address is not letting me loginto the internet.  I have read and tried every tips that was given here and still not able to fix the problem.  I really need help...  

Thanh....... please start your own question! Thanx :)

Well how about that! Microsoft now has a Technet solution to resolve the problem. Although the KB solution doesn't explain the symptoms very well, the result is very effective. In all three cases that I had been unable to resolve the connection problems via prior solutions, this new solution did the trick. Copy and paste this link, then run the download.

http://www.microsoft.com/downloads/details.aspx?FamilyID=17d997d2-5034-4bbb-b74d-ad8430a1f7c8&DisplayLang=en

I have never been a big fan of service pack 2, it seems to create more problems than it intended to fix. I have had this problem on a number of client machines and racked my brain on it for hours. winsock fix, no luck, same with drivers, manually configuring the tcpip stack, and even reinstalling it. it's something to do with spyware that bonds with the tcpip and then will make a reg entry to somehow continually disable it.

My solution: The only known way I have EVER been able to fix this is to reinstall. I know people say that's extreme. but waste 5 hours on this and reinstalling is much quicker and will fix other small problems you might be having. Try to also use a reputable spyware removal tool, the new norton has it built in.

Hope this helps everyone.

As of late, since applying the WinsockXpfix.exe and the Technet Solution above from Microsoft, I have avoided all rebuilds. Spybot and Adaware are still my favorites for removing Spyware, but be sure to download at least the WinsockXpfix.exe before performing any cleaning. This way if you remove a piece of spyware that breaks your TCP/IP or Winsock, at least you already have a way to fix it.